Contents

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

Definitions in part have been reprinted from Gerald W. Cowell's "Dictionary of Metalworking Terms" ©1982, 1971, with permission from Gardner Publications, Cincinnati, Ohio.

Abrasion

The process of reducing material by grinding instead of cutting with tools.

Abrasive

Crushed sharp crystals of grinding material used in the form of grinding wheels, polishing cloth and lapping powder.

Abrasive paper

Paper or cloth which has had small particles of emery, flint, carborundum, or similar materials fastened to it with an adhesive.

Abscissa

The distance of any point from the vertical y-axis of ordinates in a two-dimensional system of reference, measured on a line parallel to the horizonal x-axis of abscissas.

Absolute accuracy

Accuracy as measured from a reference, which must be specified.

Absolute address

An address that is permanently assigned by the machine designer to storage location. An address that indicates the exact storage location where the referenced operand is to be found.

Absolute coordinates

The values of the x, y, and z coordinates with respect to the origin of the coordinate system.

Absolute data

Values representing the actual coordinates of a point or other geometric entity on the display surface (of a terminal). The values may be expressed in the linear units of the display or in the traditional units of an engineering drawing.

Absolute dimension

A dimension expressed with respect to the initial zero point of a coordinate axis.

Absolute error

The magnitude or error disregarding the algebraic sign; the amount of error expressed in the same units as the quantity containing the error.

Absolute humidity

The weight of water vapor in a given amount of air.

Absolute pointer

A pointer implemented by retaining the address of the data pointed to.

Absolute reference point

All part coordinates are related to a fixed-zero location (x-y axis) on the machine table.

Absolute system

A numberical control system in which all coordinate locations are dimensioned and programmed from a fixed or absolute zero point.

Absolute vector

A directed line segment whose end-points are measured in absolute units from a designated origin. Contrast with relative vector.

Absolute zero

A temperature at which molecular activity theoretically ceases.

Absolute zero point

The point of absolute zero for all machine axes; the extreme point at which counting is started.

Ac-dc

Refers to an electrical device which operates on either aleternating or direct current.

Acceleration distance

The calculated distance for acceleration along an axis of motion to reach a commanded rotational or lateral speed.

Acceleration time

The time required to get any mechanical peripheral device up to its normal operation speed.

Acceleration, programmed

A controlled velocity increase to the programmed rate.

Acceptance test

A test or tests used for evaluating the committed performance, capabilities, and conformity of software and/or hardware to a predefined specification.

Access method

Any of the data-handling techniques available to the user for transferring data between main storage and input/output devices.

Access time

The time interval between the instant at which data are called for from a storage device and the instant delivery is completed.

Access time

Termination of an error condition that cannot be resolved by recovery facilities while the task is executing.

Accessory

A mechanical part which need not be a part of the machine with which it is to be used, but does permit better performance or more versatility.

Accuracy

The degree of freedom from error; that is, the degree of conformity to truth or to a rule. Accuracy is the difference between the target and the average from that target plus or minus three standard deviations, and repeatability is plus or minus three st

Accuracy study processor

A computer program used to perform calculations to assist in determining if program variables are computed with required accuracy.

Accuracy, control positioning

Accuracy, precision or reproducibility of position sensor or interpreting system and including the machine positioning servo. (may be the same as machine positioning accuracy, precision or reproducibility in some systems.)

Accuracy, machine positioning

Accuracy, precision or reproducibility of position sensor or transducer and interpreting system, the machine elements and the machine positioning servo. Cutter, spindle and work deflection and cutter wear are not included. (may be the same

Accuracy, machining

Accuracy, precision or reproducibility obtainable on completed parts under normal operation conditions.

Accuracy, measuring

Accuracy, precision or reproducibility of position sensor or transducer and interpreting system.

Accurate

Conforming exactly to a standard; without error; precise.

Acetylene

A colorless hydrocarbon gas used as an illuminant, for welding, and for cutting metals.

Acetylene cylinder

Specially built container manufactured to store and ship acetylene

Acetylene regulator

Automatic valve used to reduce acetylene cylinder pressure to a consistant torch pressure

Acid bath

An acid solution for cleansing the surfaces of gold, silver, copper, brass, and zinc objects, preparatory to electroplating; acid pickle.

Acieral

A lightweight alloy, composed of copper, zinc, nickel, iron, silicon, and aluminum. It was formerly used a great deal in the automotive industry.

Acme thread

A screw thread which has an included angle of 29 degrees, and a flat top and bottom.

Acoustic coupler

An electronic device used to interface the handset of a conventional telephone with a computer terminal. Acoustic emissions are sent to and from the handset.

Acoustic emission

Sound produced by a material as it undergoes change

Acronym

A word formed from the first letter of letters of the words in a name, term or phrase; e.g., cam from computer-aided manufacturing.

Active storage

A device (usually a magnetic core, disc or drum) which holds data or commands until required.

Actual throat

Shortest distance from the root to the face of the weld

Acute angle

An angle less than a right angle.

Adapt

A parts programming language developed by the air force for medium scale computers.

Adapter

Any device that serves to connect or fit together two parts of an apparatus.

Adapter plate

The plate-holding mold which fits platen or press in injection molding.

Adaptive control

A control system within which automatic means are used to change the system parameters in a way intended to improve the performance of the system.

Addendum

The point or portion of the tooth of a gear wheel which lies outside the pitch circle.

Address

Means of identifying information or a location in a control system; i.e., the x in the command x12345 is an address identifying the numbers as referring to a position on the x axis.

Address code

The alphabetic portion of a word (see word).

Addressable point

Any position on the display surface of a device that may be specified as absolute data in terms of that device. These positions are specified by coordinates. Such addressable portions are finite in number, and form a grid over the display surface.

Adhesion

Act of sticking or clinging.

Adhesive power

The friction existing between a driving wheel and the surface with which it is in contact.

Adjacent angle

An angle having a common side with another angle and the same vertex.

Adjustable boring tool

A tool for enlarging a hole. It has a cutter which can be adjusted to permit finishing the hole to a desired size.

Adjustable parallels

Accurate, wedge-shaped bars of hardened and ground metal, which when in use are placed with the thin end of one on the thick end of the other. The distance between the parallel top and bottom faces may be increased or decreased .

Adjustable reamer

A reamer with inserted and replaceable blades locked to the body. The blade seats are tapered so the diameter of the reamer is increased by moving the blades forward.

Adjustable tap

A tap made with inserted blades capable of radial adjustment.

Adjusting screw

A screw used to adjust or regulate the position of machine parts.

Aerolite

An alloy approximately 96% aluminum used for automotive and airplane parts.

Aerosol

An assemblage of small particles, solid or liquid, suspended in air.

Aging

A change in construction stability of a metal through quenching or cold-working.

Aiming circle

A circle or other pattern of light projected by a light pen onto the surface of the display to guide the user to an accurate positioning of the pen and/or to describe the light pen's field of view.

Aiming device

A circle or other pattern of light activated by a light pen on the display surface to assist positioning of the pen and to describe the pen's field of view.

Air carbon arc cutting

Arc cutting process which uses a carbon arc to heat the metal, an air blast to remove the material forming a gouge or cut.

Air cleaner

A device designed for the purpose of removing atmospheric airborne impurities.

Air conditioning

The process of controlling the temperature, humidty, cleanliness and distribution of air

Air filter

An air cleaning device to remove particulate from the air prior to introduction into a building or system.

Air hammer

A tool in which a hammerhead is activated by means of compressed air, conducted from the air compressor through a hose.

Air handler

See blower coil.

Air hoist

A hoisting device operated by compressed air.

Air, standard

Dry air at 70 f and 29.92 in (hg) barometer.

Algorithm

A procedure for accomplishing a given result by proceeding on a logical step-by-step basis. Computer programs are developed by this method.

Align

To set mechanisms or machines in proper relation to each other.

Alkali metals

Rubidium, lithium, caesium, sodium, potassium, and similar metals having varying photo-electric properties.

Alkaline bath

A solution for removing grease, etc., From objects to be electroplated, usually of caustic soda or caustic potash.

Allen screws

Cap screws and setscrews with a hexagonal socket in the head into which a hexagonal key (allen wrench) is inserted in order to rotate the screw.

Alligator wrench

A wrench used often in plumbing, with fixed v-shaped jaws (usually with teeth or serrations on them).

Allowance

The degree of variation permitted from a nominal specification; the total tolerance.

Alloy

A mixture, solid solution, or combination of two or more metals (i.e., brass is an alloy of copper and zinc); a substance obtained by the mixture or combination of a metal and a nonmetal; a baser metal combined with a finer one.

Almandite

A variety of mineral garnet, used for abrasive coatings on paper or cloth.

Alnic

An alloy of cobalt, nickel and aluminum used to make small permanent magnets.

Alphanumeric code

A coding system consisting of letters, digits, and miscellaneous characters.

Alternate angle

Either of two nonadjacent interior or exterior angles formed on opposite sides of a line which crosses two other lines.

Alternating current

An electric current that first flows one way in a circuit, and then the other.

Altitude

The vertical distance from the base of a figure to its highest point.

Alumen

An alloy 88% aluminum, 10% zinc, and 2% copper which can be forged and machined. It is heavier than aluminum and very strong.

Aluminum

A light, bluish-white, malleable and ductile metallic element (symbol al) found only in combination; it strongly resists oxidation, is widely used in alloys, and, by hammering and rolling, becomes as hard as iron.

Aluminum alloys

The combination of aluminum and other metals to produce castings, etc., Where strength as well as lightness is required.

Ambient temperature

The temperature of the surrounding air or material.

American screw gauge

A standard gauge for checking the diameter of wood and machine screws.

American standard pipe threads

The thread used on most pipes, and steel and wrought iron. (originally known as briggs standard pipe thread).

Ammeter

An instrument used to measure current flow

Ampere

A unit of measurement used in expressing the rate of flow in an electrical circuit

Amplifier

A device or system which provides an output different in magnitude from the output

Amplitude

An angle which controls the value of certain mathematical functions.

Analog

Anything analogous (resembling) to something else. Denotes the use of physical variables; i.e., distance, rotation, or voltage, to represent and correspond with numberical variables that occur in a computation (as opposed to digital).

Analog and digital data

Analog data implies continuity as contrasted to digital data which is concerned with discrete states. Many signals can be used in either the analog or digital sense, the means of carrying the information being the distinguishing feature.

Analog-to-digital converter

An electronic device which senses an analog signal and converts it to a representation in digital form.

Analysis

The process of resolving a problem into its first elements.

Analytical geometry

The study of geometric figures through algebraic analysis.

Analytical modeling

A technique used to represent mathematically  some physical phenomena. Such models are valuable for abstracting the essence of the subject of inquiry.

Ancony

In metalworking, a wrought iron bar, partly finished in the middle, but left larger at the ends (unwrought).

Angle

The geometrical figure formed by two intersecting straight lines; the space between the intersecting straight lines.

Angle of inclination

The angle formed by a screw thread with relation to its axis.

Angle of relief

(see relief angle).

Angle of rupture

The angle at which any material will break upon the application of sufficient strain or stress.

Angle plate

A workholding device, used mostly on milling machines, surface grinders and planers. It is composed of two plates set at right angles to each other, with holes or slots for fastening the workpiece.

Angle-iron

A rolled-steel member, l-shaped in section.

Angular

Having, forming, or constituting an angle or angles; sharp cornered; pointed; measured by an angle; pertaining to angles.

Angular cutter

A milling cutter which has its cutting face at an angle to the axis of the cutter.

Angular indexing

(see dividing head).

Angular measurement

Measurement expressing the relationship of one line to another based on the division of a circle into 360 sections, each section one degree of an angle. There are 360 degrees in a circle, 60 minutes in one degree, and 60 seconds in one minute

Angular pattern die-stock

A type of die-stock on which the handles are placed at an angle to the longitudinal axis.

Angular thread

A screw thread whose cross section is that of a triangle as opposed to a square thread.

Anneal

To heat a metal piece to its critical temperature and then allow it to cool slowly, thus reducing brittleness and increasing ductility.

Annealed tubing

Tubing which can be bent. Commercial tubing may be purchased annealed, partially annealed, or hard.

Annealing furnace

A furnace designed to heat metals to an almost fluid state, then permitted to cool slowly, to render them malleable.

Annular

Having the form of a ring; ring shaped.

Annular ball bearing

A bearing in which the balls are contained in a ring.

Annular gear wheel

A gear-toothed wheel, with the teeth positioned on the inner circumference of the wheel. An annular gear always revolves in the same direction as its pinion.

Annulus

In geometry, the space between the two circumferences of concentric circles.

Annunciator

A visual or audible signaling device, which indicates conditions of associated circuits.

Anode

Positive terminal of an electrical circuit.

Anodizing

An electrical process in a chromic-acid solution which deposits a hard surface film of aluminum oxide on aluminum parts. It serves as an excellent base for paint.

Answerback

The response of a terminal to remote control signals.

Antecedent

In mathematics, the first term of a ratio.

Anti-friction metal

A white metal developed by isaac babbitt, american inventor, much used for lining the bearings of shafts and axles, and other moving parts (see babbitt).

Anti-logarithm (math.)

A number corresponding to a given logarithm.

Antimony

A silver-white, hard, crystalline metallic element related to arsenic and tin, frequently used in alloys of tin and lead to provide hardness.

Antinode

Midway point, maximum amplitude, of a vibrating body between two nodes.

Anvil

An iron or steel block upon which forging is done.

Anvil vise

A vise whose stationary jaw has been cast in the shape of an anvil.

Aperture

A hole, or opening.

Aperture card

An opaque tab card with a rectangular hole or holes designed for the mounting or insertion of microfilm.

Apex

The pointed top or peak of a conical figure, pyramid, etc.

Application

A definable set of tasks to be accomplished as part of the work of an enterprise. An application may be accomplished partly through manual procedures and partly through computerized procedures.

Application developer

An individual responsible for tailoring the basic capabilities of the information system into a form suitable for end users, mainly through the design and implementation of application programs.

Application package

A set of programs specifically designed to perform a particular application. The working programs in a system for a user task may be classed as an application package.

Application program

Computer program devised for a specific task. A set of statements defining those tasks associated with an application that are to be executed by the computer. The working application program may be classed as a system.

Application software

Software designed to operate as a system for specific applications; e.g., the software for an interactive graphics system to carry out printed circuit board artwork layout.

Applied mechanics (phys.)

The practical application of the laws of mechanics as opposed to the theoretical.

Apprentice

A learner enrolled in a course of study administered by an employer which is correlated with employment in a related field.

Approximate

Nearly, not exact. Often used in relation to dimensions when tolerances are considerable.

Apron

The vertical plate on the front of the carriage of a lathe, where many of the controls are located.

Apt

An english-like language which describes the part illustrated on an engineering drawing and takes the form of a sequence of statements that define the part geometry and machine tool cutter operations.

Arabic numbers

Characters which denote arithmetical figures in common use in this country. (1, 2, 3, 4, 5, etc.) The arabs or moors are given credit for introducing them into europe during their occupation of spain.

Arbor

A shaft, mandrel, spindle, or axle; on a milling machine the cutter is often mounted on an arbor - on a lathe the work is sometimes mounted on an arbor.

Arbor press

A device for pressing an arbor, or shaft, into a hole, or bore of an article, when the mating parts fit tightly; or to remove the same.

Arc

Any flashing occurring between the terminals of an electric circuit when the circuit has been interrupted. Math. - any portion of the circumference of a circle.

Arc blow

Wandering of an electric arc from its normal path as a result of magnetic interference.

Arc brazing

An electric brazing process wherein the heat is obtained from an electric arc formed between the base metal and an electrode, or between two electrodes.

Arc cutting

A group of cutting processes wherein the severing of metals is effected by melting with the heat of an arc between the base metal and an electron.

Arc furnace

A furnace in which the heat is generated by an electrical arc.

Arc gouging

Arc cutting process used to cut a groove.

Arc voltage

Electrical potential (voltage) across an arc.

Arc weld

To weld by the electric arc process. (one wire of an electrode placed in contact with the metal to be welded. The electrode is quickly withdrawn to a short distance, and current passes across the air gap between the work and the electrode.

Arc, clockwise

An arc generated by the coordinate motion of two axes in which curvature of the path of the tool with respect to the workpiece is clockwise, when viewing the plane of motion in the negative direction of the perpendicular axis.

Arc, counterclockwise

An arc generated by the coordinate motion of two axes in which curvature of the path of the tool with respect to the workpiece is counterclockwise, when viewing the plane of motion in the negative direction of the perpendicular axis.

Arcing

Forming an arc, as in a broken circuit, or at the brushes of a generator.

Area of a circle

Pi times the square of the radius, or ½ pi times the diameter squared. Pi is usually given the value of 3.1416 unless very exacting mathematical solutions are required.

Arithmetic

The science of numbers and computing with numbers under the four operations of addition, subtraction, multiplication, and division.

Arithmetic unit

The unit of a computing system that contains the circuits that perform arithmetic operations.

Arm

In structural steel, one of the wings or flanges of angle-iron. In machinery, the handle of a trip hammer which receives the impluse of the cams.

Armature

The cylindrical, laminated iron core which revolves the coils of insulated wire through the magnetic field of a dynamo.

Armored hose

In hydraulics, hosepipe strengthened externally by a protection of spirally coiled wire.

Array

An arrangement of elements in one or more dimensions.

Arrow diagram

A network representation of a grammar in which each valid statement corresponds to a path through the network.

Artificial intelligence

A term used to describe the use of computers in such a way that they perform operations analogous to the human abilities of learning and decision making.

Artificial language

A language based on a set of prescribed rules that are established prior to its usage.

Artisan

A person skilled in some trade or art both in manual dexterity and information related to the skill; a mechanic or journeyman.

Artwork generator

A visual display unit used to produce an artwork master from a complete description of the geometry that is required to fabricate a device.

Artwork master

A precision representation of a pattern that is to be used photographically in a production operation. The master may be prepared multiple size and reduced photographically or prepared full scale.

Ascii

American standard code for information interchange.

Aspect ratio

The ratio of an object's height to its width. In graphics this ratio usually pertains to the display area of a rectangular crt or to the characters or symbols drawn by the hardware or software character generator.

Assemble

To prepare a machine language program from a symbolic language program by substituting absolute operation codes for symbolic operation codes and absolute or relocatable addresses for symbolic addresses.

Assembly

The finished separate pieces put together according to the assembly drawing.

Assembly drawing

A drawing which shows all the parts of a structure, but does not include the dimensions of the detail drawings.

Assembly language

A computer language organized to transform operational codes into a machine language. The result is a character-for-character transformation.

Assembly line

A moving track or belt, or an arrangement of machines so that a sequence of operations may be performed in the proper order to produce a manufactured article.

Assembly parts list

A list of all parts, which may include subassemblies comprising a particular assembly, as used in the production process.

Asynchronous

Without reference to timing relationship. Hence, as applied to program execution, unexpected or unpredictable with respect to instruction sequence.

Atmospheric pressure

The pressure exerted on the earth's surface by the weight of the atmosphere.

Atom

Smallest whole part of an element.

Atomic hydrogen welding

A combination of gas welding and arc welding.

Atomize

To break up a jet or stream of liquid into a fine spray resembling dust or smoke.

Attachment

A device used with a machine to improve its work or increase its versatility.

Attention key

A function key on terminals which causes an interruption of program execution by the central processing unit.

Attribute

A characteristic; e.g., attributes of data include record length, record format, data set name, associated device type and volume identification, use, or creation date.

Audio frequencies

Frequencies that can be heard by the human ear (usually 15 cycles to 20,000 cycles per second).

Audio response unit

An output device that provides a spoken response to digital inquiries from a telephone or other device. The response is composed from a prerecorded vocabulary of words and can be transmitted over communication lines.

Audit trail

A computer file upon which is written all input and output transactions from a computer program or system. It is used to reconstruct important (such as financial transactions) in case of a computer failure, or to compile usage statistics.

Austenite

High temperature form of steel.

Autogenous soldering

The art of process of lead burning, in which two pieces of lead are fused together by means of hydrogen flame.

Autogenous welding

A method of welding which unites metal pieces with heat from a torch flame, usually at 6,300 degress farenheit.

Automated assembly

Assembly by means of operations performed automatically by machines. A computer system may be used to monitor the production level and the quality level of the assembly operations.

Automated process planning

Creation of process plans for items in a given family with either partial or total computer assistance.

Automated verification systems

Computer programs that address the source code by generating and inserting counters at strategic points to provide measures of test effectiveness. They provide data that details how thoroughly the source code has been exercised.

Automatic

Having a self-acting mechanism by which certain operations are performed under predetermined conditions.

Automatic bar machine

Same as automatic screw machine, but in recent years the term bar machine is coming into wider use, because of the wide variety of work other than the manufacture of screws (see automatic screw machine).

Automatic center punch

A center punch so constructed that when pressure is applied, a spring controlled punch contained within the handle is released with sufficient force to leave its mark on metal.

Automatic coding

The use of a data processing system to perform some stages of the work involved in preparing a program.

Automatic control

Control accomplished without human intervention, such as by a device that automatically senses measurements of one or more physical variables involved in a process, automatically performs calculations with the variables, and automatically

Automatic data processing

Data processing by electronic computers and tabulating equipment so organized to produce desired results with a minimum of human effort.

Automatic drafting

The generation of engineering drawings or artwork masters from data base descriptions of a real artifact.

Automatic gear cutter

A specialized machine, developed from the universal milling machine and designed for the production of gears or toothed wheels. It is automatic in that once the operator has placed the blank in the machine it rotates the work after each to

Automatic grouping

The machine-assisted collection of all those display elements which share common boundaries to form an identifiable display group and which may be manipulated as a single unit.

Automatic overload switch

A switch attached to a machine which automatically opens the circuit when an excessive load is placed on the machine, thus shutting the machine off.

Automatic screw machine

A machine for the accurate, fast production of small parts, such as screws and bolts, etc. The machine performs without an operator once it has been set up.

Automatic welding

Welding with equipment which performs the entire welding operation without constant observation and adjustment of the controls by an operator. The equipment may or may not perform the loading and unloading of the work.

Automation

The automatic transfer of one unit of a complex industrial product to a succession of self-operating machines.

Auxiliary

Giving or furnishing aid or support, generally in a secondary or subordinate manner; supplementary, as an auxiliary view in a drawing.

Auxiliary function

A function of a machine other than control of the coordinates of a workpiece or tool. Includes functions such as miscellaneous functions, feed, speed, tool selection, etc. Not a preparatory function.

Auxiliary operations

Operations involving peripheral components of the computer without the use of its central processing unit. Examples are tape-to-printer, card-to-tape. Such operations free the main computer for other work.

Auxiliary storage

Storage which supplements main memory, such as disk, tape, drum, or some other type of storage.

Available machine time

The elapsed time when a device is in operating condition, consisting of both idle time and operating time; sometimes, available up time.

Available material

A term usually interpreted to mean material available for planning and thus including not only the on-hand inventory but also inventory on order. Material available for use would, of course, be only the material on hand which has not been assigned.

Available work

Work that is actually in a work center ready to be worked on as opposed to scheduled work which may not yet be on hand.

Average

Midway between extremes; the mean of a collection of quantities, obtained by dividing the sum of the quantities by the number of the quantities.

Avoirdupois weight

The ordinary commercial standard of weights, used for nearly all articles with the exception of jewels and precious metals.

Axes of coordinates

Two intersecting lines, one vertical, called the axis of ordinates, the other horizontal, called the axis of abscissas, by means of which the location of a point in a plane may be determined.

Axial pitch

See pitch.

Axiom

A self-evident truth, too simple to require demonstration or proof (e.g., two things which are equal to the same thing are equal to each other).

Axis

The central line about which parts of a body are symmetrically arranged. An imaginary line through the center of a drawing for purposes of measurement or reference.

Axis inversion

The reversal of normal plus and minus values along an axis which makes possible the machining of a left-handed part from right-handed programming or vice versa.

Axis of a weld

Imaginary line along the center of the weld.

Axis of symmetry

An imaginary central line around which a symmetrically developed body is formed, and in which the center of gravity is found.

Axle

A shaft which carries a wheel, such as the axle of an automobile or other vehicle.

Babbitt

A soft, white, anti-friction alloy of tin, copper, and antimony. Any of a group of similar alloys.

Babbitt bearing

A bearing surface lined, bushed, filled, or faced with babbitt metal.

Back gear

An arrangement of gears by which power is increased, and speed proportionately decreased, as on a lathe.

Back rest or follower rest

A device for a lathe to provide support for long slender work. It moves with the carriage, staying in position opposite the cutting tool.

Backfire

Short pop of the torch flame followed by flameout.

Background mode

A computer is operating in background mode when a job is being carried out simultaneously with another job or jobs but with lower priority on computer time and without the facility for user intervention during execution.

Background processing

The automatic execution of lower-priority programs when higher-priority programs are not using the system resources.

Backhand welding

Moving the weld in opposite direction to which the flame is pointing.

Backing

Material placed on the root side of a weld to control penetration.

Backing off

Reversing the direction of a tap or reamer, etc., For the purpose of removing chips from the flutes, or metal adhering to the cutting edge of the tool, for the purpose of reducing friction.

Backing ring

Metal ring placed inside of a pipe before butt welding.

Backlash

A relative movement between interacting mechanical parts resulting from looseness.

Backlog of orders

The sum of all unfilled orders waiting to be filled or processed.

Backup

In flash and upset welding, a locator used to transmit all or a portion of the upsetting force to the workpieces.

Backup copy

A copy of a file or data set that is kept for reference in case the original file or data set is destroyed or damaged.

Backward extrusion

Forming with a punch and die so designed that metal flows between the bottom of the die and the face of the punch and then rearward around the punch.

Backward scheduling

A scheduling technique where the schedule is computed starting with the due date for the order and working backward to determine the required start date.

Bakelite

Trade name of a group of thermosetting plastics formed by the chemical reaction of phenol, formaldehyde, and their derivatives having a wide range of properties and uses, particularly insulation.

Balance wheel

A flywheel. A wheel which imparts regularity to the movements of a machine or engine.

Balanced pulley

A pulley which has been adjusted for balance to prevent excessive wear on bearings.

Balancing machine

A machine which measures the out-of-balance of a wheel or other similar piece and shows the amount and location of the needed correction.

Ball and socket joint

A joint in which a spherical object, or ball, is recessed into a fitted socket, permitting movement in any direction within certain limits.

Ball bearing

A hardened steel ball, precision ground to a specified dimension, which when placed with others in a bearing race, permit free revolving of a shaft in a stationary support or vice versa.

Ball check valve

A type of valve which stops the flow of the pipe's contents by a ball which rests on a seat. Pressure causes the ball to rise from the seat and permit flow. When the pressure is reversed or removed the ball returns to the seat and closes the valve.

Ball race

A groove which contains the balls in a ball bearing.

Ball reamer

A type of rose reamer, hemispherical in shape, which is used to finish the recess for a ball joint.

Ball-peen

A hemispherical peen on a hammerhead, used especially for riveting (also: ball-pene; ball-pane).

Ball-peen hammer

A kind of hammer used often by machinists. It is flat on one end of the head for striking punches, chisels, etc., And has a peen (round end) on the other end of the head for riveting, etc.

Ballast resistor

Controls voltage applied to the coil.

Balling

The act of forming wrought iron balls in a furnace before their passage through the molding machine (squeezer).

Band saw

A saw which carries an endless blade on pulleys, made for both metal and wood cutting.

Band twisting

The technique used to coil an endless saw blade for storage.

Bar

A long piece of metal, sometimes referred to as bar stock.

Bar folder

A machine which folds or edges strips or sheets of metal to form angles, square joints, and other similar operations.

Bar lathe

A lathe whose bed is made in a single piece, usually of a triangular section.

Bar-shear

A machine for cutting metal bars. It has a fixed lower blade in a strong frame, and a vertically reciprocating upper blade, between which the metal is sheared.

Barium

A silvery white, malleable, lustrous metal used in some alloys.

Barrette file

A triangular file used by toolmakers and diesinkers, cut on the bottom only, the other two sides being safe edges.

Barrow-ladle

A foundry ladle mounted on a low carriage with handles and legs at the rear, and two wheels in front, used for moving molten metal about the foundry.

Base circle

In gear drawing, the circle on which the involute gear tooth is constructed.

Base plate

A heavy iron casting used as a foundation for a machine.

Basic

An algebra-like computer language used for mathematical problem solving. One of the more simple computer languages.

Basic software

Generalized software supplied with computers to permit them to perform their functions and interface with other computers or systems.

Bastard file

A coarse-cut file, but finer than a first cut file. The designer was named barsted, and the common term bastard has been corrupted from that.

Batch manufacturing

Same as batch production.

Batch mode processing

To put through a manufacturing process at one time. A technique by which items to be processed must be coded and collected into groups prior to processing. Mode of computer operation in which independent jobs are saved up for execution.

Batch processing

Pertaining to the technique of executing a set of programs such that each is completed before the next program of the set is started. A method of processing jobs on a computer where they are organized and handled one at a time.

Batch production

Noncontinuous processing of unlike parts.

Bath metal

An alloy consisting of a pound of copper to four and a half ounces of zinc.

Battery

An electrochemical device that produces electricity.

Baud

A unit signaling speed equal to the number of discrete condition or signal events per second.

Bauxite

The principal source of aluminum. It is often used as a lining for furnaces and in the preparation of aluminum and alumina.

Bay

The rectangular area formed between four adjacent columns or equivalent points.

Bead sleekers

Molders' sleeking tools used for smoothing the impressions of beaded work in the sand molds (also called bead tools).

Beading

The forming of a bead to stiffen or ornament a piece of work.

Beading machine

A machine which does beading.

Beak'horn stake

A metal stake which has one end rectangular in section and the other end rounded and tapered, used for shaping and bending metal.

Beak-iron

An iron implement to fix in a socket or bench vise and shaped in various forms to use in shaping interior surfaces in sheet metal work.

Beam drill

A drilling machine designed for large work, somewhat similar to a radial drill press but having a beam supported at both ends which carries the drilling mechanism, instead of the radial arm.

Bearing

Amount of surface contact between two parts (in relation to scraping). A part that rests on something, or on which something rests (see roller, ball, and babbitt bearing).

Bearing cap

The top half of a journal bearing.

Bearing pressure

In mechanics, the pressure of a revolving shaft upon its bearing, usually measured in pounds per square inches of projected area.

Bearing surface

The area of a surface upon which a shaft rotates; the surfaces of bearing parts which are in mutual contact. The larger the bearing surface, the less the amount of friction per unit of surface, since pressure is then distributed over a larger area.

Bed

Fixed portion of a machine structure which may provide a work mounting surface and will support other machine elements; for example, table, ways, column, saddle, gantry, etc.

Bed-plate

See base plate.

Bedding

A molding operation consisting of filling the drag flask with sand and forcing the pattern down to the desired position, then firmly packing the sand about the pattern.

Beginning tape marker

A marker on a magnetic tape used to indicate the beginning of the permissible recording area.

Behind-the-tape reader

A means of inputing data directly into a machine control unit from an external source other than a tape reader.

Bell

In pipefitting, the recessed or enlarged end of a cast iron pipe, into which the male end of the next pipe fits; also called the hub. The conical cover of a blast furnace, collecting the gasses used in regenerative stores.

Bell center-punch

A shop tool for quickly locating the centers of small shafts of various sizes, and center-punching them.

Bell chuck

A bell-shaped form of lathe chuck, within which the work is held by adjustable setscrews. Usually used for small work.

Bell crank

A crank, or lever, with two arms meeting at a 90 angle.

Bell metal

An alloy of copper and tin; resonant, brittle and hard.

Bellmouth hole

A hole which is larger in diameter at the start of the hole.

Bellows

A device with flexible sides, used for compressing and directing a current of air. It is often used in foundrys to blow sand from patterns, etc.

Belt

A band of flexible material, which passes around and communicates motion from one pulley to another.

Belt clamp

A device for holding the two ends of a belt together while they are being laced for connected.

Belt conveyor

An endless belt running over rollers and/or pulleys used to transport materials.

Belt dressing

A compound used on belts to prevent slippage.

Belt hook

A device for shifting belts manually. Used a great deal in older machine shops where many machines were driven from overhead pulleys.

Bench hand

One who makes and/or fits parts by hand. A qualified bench hand should have approximately the equivalent training time as a machinist.

Bench lathe

A small lathe which is mounted on a work bench instead of its own separate foundation. Much used by pattern makers and jewelers.

Bench shear

A shear, mounted on a bench, used for cutting sheet metal.

Bench work

Work which is done at the bench or vise as distinguished from lathe or machine work, also work of a fitter as distinguished from that of an erector.

Benchmark

A point of reference from which measurements can be made.

Bending roll operator

A skilled workman, who bends steel plates to specified curves, arcs or cylinders, by adjusting the tension on the bending rolls to obtain the desired result.

Bending rolls

Heavy cast iron or steel rolls set in strong supports, used for straightening crooked steel plates, or curving them into desired arcs.

Beryllium

One of the exotic metals, weighing nearly 80% less than steel but with about equal strength. Often used in nuclear reactors, missiles, and aircraft. It is brittle, but easy to machine.

Bessemer converter

The vessel used to make steel from cast iron, named after the inventor of the steel-making process.

Bessemer steel

A mild (soft) steel produced by the bessemer process and used for girders, rails, boilers, etc.

Between centers

In lathe work, the mounting of the work between two 60 centers, which in turn are mounted respectively in the spindle of the headstock and the spindle of the tailstock.

Bevel

Any inclination of two surfaces other than 90 ; oblique; slanting. To cut or bring to a bevel.

Bevel gear

A gear with the teeth cut on an angle in order to transmit power in any desired direction.

Bi-tangent

A line that touches a curve at two points.

Bill of material

A listing of all the subassemblies, parts, and materials that go into an assembled product showing the quantity of each required to make one assembly.

Binary

Pertaining to a characteristic or property involving a selection, choice, or condition in which there are two possibilities. Pertaining to the number representation system with a radix of two.

Binary code

A code in which each allowable position has one of two possible states. A common symbolism for binary states is 0 and 1. The binary number system is one of many binary codes.

Binary coded decimal system

A system of number representation in which each decimal digit is represented by a group of binary digits forming a character.

Binary search

A dichotomizing search in which the number of items of the set is devided into two equal parts at each step of the process. Appropriate adjustments are usually made for dividing an odd number of items.

Binder pulley

A pulley whose function is not to transmit power, but to tighten the belt between a driving and a driven pulley.

Bipolar

Having two magnetic poles (also dipolar).

Biquadractic

In mathematics, the square of a square; pertaining to the fourth power.

Birmingham wire gage

Originally the english standard for wire and sheet metals, now used for sheet metal only. For wire, the imperial wire gage is now the standard.

Bisect

To divide equally into two parts, especially in relation to angles.

Bistable

Pertaining to a device capable of assuming either one of the two stable states; e.g., electronic flip-flop.

Bit (1)

A binary notation of either 1 or 0. In a computer a bit is a basic element that electronically carries the binary 1 or 0.

Bit (2)

The cutting tool for a lathe after it has been ground and shaped ready for use (see tool blank).

Bit density

A measure of the number of bits recorded per unit of length, area or volume.

Bit rate

The speed at which bits are transmitted, usually expressed in bits per second.

Black box

A system of which only the input and output signals can be observed. A generic term used to describe an unspecified device which performs a special function or in which known inputs produce known outputs in a fixed relationship.

Black varnish

Ordinary varnish stained by the addition of lamp-black. It is used by pattern makers.

Blackwork

Work of the blacksmith in contrast to the whitework of the silversmith.

Blade

The cutting part of edged tools. Also the steel rule which is a part of a combination square set.

Blank

In engineering, a piece of metal forged, cast, or roughly cut to a desired shape, prior to accurate finishing. In sheetmetal, a disc or plate cut to the proper size preparatory to other operations. In coining, a disc of metal cut from a sheet and annealed

Blank flange

In pipefitting, a plate for covering the end of a pipe. The term is also used to refer to a pipe flange in which the bolt holes have not been drilled.

Blanking

A stamping operation in which a die is used to shear or cut a desired shape from flat sheets or strips of metal.

Blast furnace

A masonry tower 60 to 100 feet high, lined with thick firebrick and cased with iron, used in smelting to reduce iron ores to cast or pig iron.

Blast gate

Sliding damper.

Blister copper

A fine copper which is cast into slabs for further refining after having been roasted then melted. Gasses escaping from the molten copper give it a blistered effect, hence the name. It is about 96% pure, and further refining is done by electrolysis.

Block

A word or group of words considered as a unit and separated from other such units by an end-of-block character.

Block address format

Means of identifying words by use of an address specifying the format and meaning of the words in a block.

Block count readout

Display of the number of blocks that have been read from the tape derived by counting each block as it is read.

Block length

The total number of records, words, or characters contained in one block.

Block-by-block mode

A mode of operation on a numberically controlled machine tool in which one block at a time is read by the tape reader and then acted upon by the machine.

Bloom

In iron making, the ball of spongy iron produced from the puddling furnace.

Bloom steel

Steel made in open hearth and similar processes and rolled into blooms.

Blooming mill

The roll train and appurtenances which handle the bloom, or the puddle bar train, also the heavy rolling mill which shapes the large ingots formed in the bessemer process.

Blow

In foundry work, the act of ejecting molten metal from the mold when pouring, so called because of the noise made by air and gasses being displaced in the process.

Blower

A fan used to force air under pressure.

Blowhole

A bubble in a metal casting, caused by air or gas being imprisoned in the mold: it is considered a defect.

Blowing cylinders

Cylinders used to conduct compressed air into the blast main of a blast furnace.

Blowing-in

The operation of starting up or readying for use a blast furnace that is new or has been shut down. Blast furnaces are usually in continuous operation for years at a time.

Blowing-out

Shutting down a blast furnace.

Blown

A casting which is honeycombed with blow-holes is referred to as blown.

Blown-in

A blast furnace in working order is said to be blown-in or in blast. It often takes a month to blow-in a furnace.

Blowtorch

A tool used for removing old paint, soldering, brazing. It utilizes a vaporized spray of alcohol, benzine, etc., Which when ignited produces an intensely hot flame.

Blueprint

A plan or drawing made by printing on sensitized paper. Any detailed plan.

Bluer

A semi-skilled worker who blues gun barrels. The process is accomplished by the use of chemicals and heat.

Bluing

A low-temperature heat treatment of springs after fabrication, to relieve the cold-working residual stress created by coiling and forming.

Bluing

In metalworking, heating metal until it assumes a blue color, as a gun barrel.

Blunt file

A file which is only imperceptably tapered, resulting in a blunt end, contrasted to a tapered file which has a nearly sharp point.

Body

The main portion of a part.

Body core

The main core of a mold, as distinguished from branch cores.

Boiler plate

Once wrought iron was used for boiler plate, now, however, steel is widely used for this purpose. It is generally required to have a tensile strength of from 60,000 to 72,000 lbs., And an elongation of from 18 to 20%.

Boilermaker

A man who has learned to bend, shape, and assemble boiler plate, and the man who fastens the plates together, the riveter.

Boiling point

The temperature at which the addition of anyheat will begin to change from liquid to a vapor.

Bolt

A metal pin with a forged head on one end, usually six sided, and a thread on the other designed to accommodate a nut. It is usually used to fasten or secure something in place.

Bolt circle

A circle whose circumference forms the center line of a number of bolt holes. Much used in pipe flanges and in the circular covers of openings, as in a boiler.

Bolt cropper

See bolt cutter.

Bolt cutter

A type of heavy snip, manually operated, but which can develop great power by the use of toggle-joint levers. It is capable of cutting heavy bolts, and similar metal objects.

Bolt extractor

A hydraulic machine designed to force bolts out of couplings, etc., When they have rusted fast, and for other like purposes (also called bolt forcer).

Bomb out

The complete failure of a computer routine requiring a restart or reprogramming.

Boolean

Pertaining to the processes used in the algebra formulated by george boole.

Boolean algebra

A process of reasoning or a system of theorems, using a symbolic logic and dealing with classes, proposition, or on-off circuit elements. It employs symbols to represent operators such as" and, or, nor, nand" to permit mathematical calculations.

Bootstrap

A technique or device for loading the first few instructions of a routine into storage and then using them to bring in the rest of the routine.

Bootstrap loader

A computer program whose first few instructions are sufficient to bring the rest of it into the computer from an input device.

Bore

To enlarge a hole by means of a boring tool. An interior cylindrical surface as in a gun.

Boring

A machine operation consisting of enlarging a hole to a specified dimension with a boring tool.

Boring machine

A machine tool used in boring large cylinders, etc., The cutting tool revolving on fixed supports, and the work clamped to the table of the machine, which provides the feed motion. Often called a horizontal boring mill.

Boring mill

A machine basically like a lathe on end, or vertical lathe. The work is clamped to a circular table, while the tool is mounted on a cross rail similar to a planer. Used usually for rather large work.

Boss

A projection, usually cylindrical, on a casting or forging.

Bottoming tap

See tap.

Box wrench

A wrench whose gripping edge completely encircles the nut or bolt upon which pressure is to be brought.

Brace wrench

A box spanner or socket wrench which has a handle like a carpenter's brace, which permits rapid operation; a lug wrench for removing the nuts on an automobile wheel.

Bracketing

Numberical procedure in which the result desired is searched for, first by incrementing the independent variable in large steps, and then in successively smaller steps as the location of the result is approached.

Brake

To bend a metal piece to desired radius or angle on a brake machine.

Brake horsepower

The horsepower required to drive a fan

Brake operator

A sheet metal worker who operates a brake machine.

Branch chuck

A lathe chuck designed with four branches turned up on the ends, each branch containing a screw to grip the work.

Brass

A zinc and copper alloy of varying proportions, occasionally including small amounts of tin or lead.

Brass furnace

Furnace for melting brass, generally coke-fired. The alloy is placed in crucibles for melting.

Brass moulder

A workman who specializes in casting and moulding brass.

Braze

To solder with hard solder made of brass (an alloy of copper and zinc).

Brazier

A person who works with sheet brass or copper especially in manufacturing domestic or culinary utensils.

Brazing

Joining metals by the fusion of nonferrous alloys that have melting temperatures above 800 deg. F. But lower than the metals being joined.

Breadboard

Lab terminology for an experimental circuit setup exposed on a board for portability and ease of assembly or disassembly or modification.

Break lathe

See gap lathe.

Breakpoint

A specific place in a program or sub-routine that facilitates debugging by requesting interruption for manual evaluation and/or modification before continuing execution.

Briggs' standard pipe thread

A 60 angle thread, slightly rounded on top and bottom, with a taper of 1/32 inch per inch. It is standard in the u.s. for wrought pipe.

Bright red heat

In tempering, a heat of approximately 1800 f. At this heat, the metal is a bright red, with the black scale on the surface of iron thrown into relief against the red background.

Brinell

A type of testing to determine the hardness of a metal, alloy or similar material as measured by the area of indentation produced on its surface by a rigid steel ball of given diameter acted upon by a given force.

Briquetting

In power metallurgy, when a powder blend is fed into a die cavity, pressures applied to compress it to a desired shape range from 15 to 50 tons per square inch. This operation is known as briquetting.

Britannia metal

A white metal alloy, often mistaken for pewter, used for making tableware, etc.

British thermal unit (btu)

The amount of heat necessary to change the temperature of one pound pf water 1 degree farenheit.

Brittleness

The characteristics that cause metal to break easily.

Broach

To finish the inside of a hole to a shape usually other than round with a long cutting tool which has a series of teeth that gradually increase in size.

Broadband

Communication channel having a band-width greater than a voice-grade channel and therefore capable of higher-speed data transmission.

Bronze

A reddish-brown alloy, often of copper and tin, but sometimes made of copper and manganese, aluminum or others.

Brown and sharpe gauge

The standard gauge in the u.s. for determining the size of wire. The gauge number decreases as the diameter increases, and sizes range from number 40 (.00314 inch) to number 0000 (.460 inch).

Brushes

Sliding contacts, usually carbon, that make an electrical connection to the rotating part of a motor electrical connection to the rotating part of a motor or generator.

Buff

To polish with a buffing wheel (a general term applying to all soft wheels used in polishing, such as felt and cloth).

Buffer

A routine or device used to compensate for a difference in rate of flow of data, or time of occurrence of events, when transmitting data from one device to another.

Buffer storage

A place for storing information in either a computer or a control unit so that it is immediately available for action once the previous instructions have been completed.

Buffing

The process of bringing out the luster of metal. Buffing is occomplished by using cloth wheels, usually cotton or muslin discs sewed together, and a tripoli compound.

Buffing lathe

A machine used for polishing operations, usually with the use of buff wheels.

Bug

A mistake or malfunction. An error or flaw in a program that renders it incapable of performing the objectives for which it was written. Debugging is the process of finding and eliminating programming errors.

Bullnose tool

A term sometimes applied to a type of roughing tool for a lathe. It usually has a rounded point wider and stronger than an ordinary round-nosed tool.

Burnish

To polish to a smooth finish by working a smooth tool against moving or revolving surfaces.

Burr

The rough, usually sharp edge left on metal after a cutting or shearing operation. The act of removing a burr.

Burring reamer

See countersink.

Burst

In data transmission a sequence of signals counted as one unit in accordance with some specific criterion or measure. To separate continuous form paper into discrete sheets.

Bus

One or more conductors used for transmitting signals or power.

Busbar

A solid bar or wire for making a common electrical connection

Bushing

A metal sleeve or bearing upon which a pulley or wheel turns. A liner for a hole to make it smaller.

Butt joint

A joint between two members lying approximately in the same plane.

Butt weld

A type of weld where the two edges to be welded are simply placed against each other, as distinguished from lap weld or scarf weld.

Buttress thread

A thread designed to withstand great strain, one side of the thread is angled, the other nearly vertical.

Bx cable

A flexible metallic armor for covering wires for protection.

Byte

A series of computer binary bits, organized together to hold a symbol letter, or number in a computer. Sometimes called a word. A word or byte may be comprised of nine, twelve, or fifteen bits for example

C clamp

A common form of clamp shaped like the letter "c".

C washer

A washer with one side open so that it may be slipped off the bolt when the nut is loosened, but making it unnecessary to remove the nut completely.

C.a.m.

Computer-aided manufacturing. The use of computers to assist in any or all phases of manufacturing.

C.f.m.

Cubic feet per minute.

Cable

Insulated wires for conducting electricity.

Cad

Computer-aided design. Using computers to aid in designing products.

Calcite

A flux used in the manufacture of pig iron and steel. More commonly known as limestone.

Calibrate

To graduate a measuring instrument into appropriate units.

Calibrations

The marks on a measuring instrument, as the marks on a rule which divides the inch into fractional parts.

Caliper

A machinist tool which is made in two basic designs, one, the inside caliper, for measuring the diameter of circular work inside - bores, holes, cylinders, etc.; The other, outside caliper, for measuring circular work giving outside diameter measurments

Callup

A request by the user asking the computer to perform a certain function.

Cam

A mechanical device used to change rotary motion to some other pattern of motion such as reciprocal or intermittent.

Cam lobe

A rounded projection on a cam.

Cam vise

A vise whose opening and closing depend on cam action.

Camber

The deviation of a side edge from a straight line. The measurement is taken by placing a straight edge of specified length on the concave side and measuring the greatest distance between the strip edge and the straight edge.

Camera, planetary

A type of microfilm camera in which the document being photographed and the film remain stationary during the exposure.

Camera, rotary

A type of microfilm camera that photographs documents while both document and film are attached to transport mechanisms which move the film during exposure, so that there is no relative movement between film and document.

Camera, step-and-repeat

A type of microfilm camera which can expose a series of separate images on an area of film following a predetermined format, often rows and columns.

Cancel

A command which will discontinue any fixed cycles or sequence commands.

Canned cycle

See fixed cycle.

Canned routine

A standardized computer routine which may be called up repeatedly.

Cap screw

A machine bolt which may be used without a nut.

Capacitor-start motor

A type of single-phase, a.c. induction motor in which a starting winding and a capacitor are placed in series to start the motor.

Capacity loading

Work center loading where work will be rescheduled into other time periods if capacity is not available for it in the required time period.

Cape chisel

A narrow blade chisel for cutting keyways, grooves, etc.

Capillary tube

A refrigerant control consisting of a small diameter tube which controls flow by restriction.

Carbon-arc

An arc-welding process wherein a carbon or graphite electrode is used with or without the use of a filler metal.

Carbonization

The preparation of low-carbon steel for heat treatment by heating for several hours at about 2000 f, while it is packed in some carbonizing material, then allowing it to cool slowly.

Carborundum

A trade name for certain abrasive products, often misused as a generic name for silicon carbide.

Carburize

To heat a low carbon steel to approximately 2000 f for several hours in a box packed with carbonizing material, then allowing to cool slowly in preparation for heat treatment.

Card image

A one-to-one representation of the contents of a punched card.

Carriage

That part of a lathe which carries the cutting tool assembly and many of the controls. It rides the ways of the lathe between the headstock and the tailstock.

Carriage bolt

A bolt with a square neck which prevents the bolt from turning when the nut is being tightened. It usually has a button or oval head.

Carriage return

The operation that prepares for the next character to be printed or displayed on the specified first position on the same line.

Carrier

Same as lathe dog.

Cartridge

A container enclosing processed microforms, designed to be inserted into readers, reading-printers, and retrieval devices; used with a single core for roll film.

Case harden

To harden the outer surface of carburized steel by heating to critical temperature and then quenching in oil or water.

Cassette

A double-core container enclosing processed roll microfilm designed to be inserted into readers, reader-printers, and retrieval devices.

Cassiterite

The ore from which tin is obtained.

Cast iron

Iron most commonly used, which has been cast in molds. It cannot be tempered, forged, or rolled, and has a high carbon content.

Cast steel

Steel which has been made into a desired shape by the casting method.

Castellated

Shaped like a castle. Castellated nuts have regularly spaced grooves on one side so that cotter pins may be inserted through the grooves and a hole in the bolt to prevent inadvertant backing off of the nut.

Casting

Shaping a part by pouring molten metal, etc., Into a sand mold or die and allowing it to cool until solid.

Cat head

A collar or sleeve which fits over irregular shaped objects permitting it to be supported in a steady rest. Adjusting screws in the cat head permit the work to be centered in the steady rest.

Cathode ray tube

An electronic vacuum tube containing a screen on which information may be displayed.

Cell

The dedicated assignment of manufacturing stations to fabricate a family-of-parts in a manner integrated by support hardware and software.

Cell model

A graphic representation of a human-directed function, which has elements of input, control, processor activity, and output.

Cemented carbides

Tips for cutting tools developed through powder metallurgy. Pulverized carbides are fused into hard tips which are used for the high speed cutting of metals. Until the development of cermets, they were the hardest tools made by man.

Center

A fixed point about which the radius of an arc or circle moves.

Center distance

The distance between the centerlines of holes, shafts, gears, etc.

Center drill

Often called combined drill and countersink, the center drill is a short drill used to center work and provide an accurate starting point for standard drills. It is also used to drill a shallow hole with an angled opening.

Center gauge

A flat gauge with a 60 degree point and 60 degree v's cut into it; used to set up a threading tool prior to chasing threads on a lathe.

Center head

A device, usually a part of a combination square set, used with an attached blade in locating the center of round workpieces.

Center line

In blueprints, the line composed of alternating long and short dashes which indicate the axis of a symmetrical part.

Center punch

A punch approximately 3 or 4 inches long used in layout work. The end is ground to a sharp point at a 90 angle.

Center, dead

A stationary center.

Center, live

A rotating center.

Centerless grinder

A grinding machine with a high speed grinding wheel opposite a regulating wheel moving slowly in the opposite direction. The work is positioned between them on a rest provided for that purpose.

Centers

Lathe accessories which are mounted in the headstock and tailstock to support the work. The 60 included angle of the pointed ends fit into centerdrilled holes in the workpiece.

Centigrade

A temperature scale with the freezing point of water at zero degrees, and the boiling point at 100 degrees.

Centimeter

A measure of length in the metric system equal to 0.3937 inch, or the one-hundredth part of a meter.

Central angle

An angle whose vertex is the center of a circle and whose sides are radii.

Central processing unit

A unit of a computer that includes circuits controlling the interpretation and execution of instructions.

Centrifugal casting

A casting technique in which the mold is rotated during puring and solidification the metal.

Ceramics

The art of producing things from baked clay; clay products.

Cermets

A combination of metal and ceramics which has excellent resistance to high temperatures. It is becoming increasingly popular in the use of high speed cutting tools.

Chad

The pieces of material that are removed when punching holes in tape or cards.

Chadless tape

A punched tape wherein only partial perforation is completed and the chad remains attached to the tape.

Chain hoist

A chain used instead of a rope in what is basically a block and tackle arrangement.

Chain pulley

A pulley or sheave wheel with depressions designed to engage the links of a chain.

Chain transmission

A useful means of transmitting power when the driver and the driven shafts are too far apart to permit gearing and too close for belts.

Chaining

A system of storing records in which each record belongs to a list or group of records and has a linking field for tracing the chain.

Chaining search

A technique for retrieving data from a file by using addresses in the records that link each record to the next in the chain.

Chamfer

The flat surface formed by cutting off a sharp corner, usually having an angle of 45 degrees .

Change letter

One of a sequentially assigned series of characters used to distinguish between different versions of documentation associated with a part number or drawing number.

Change order

A formal notification that an order must be changed in some form. This can either result from changed data or specifications by the customer, an engineering change, or a change in inventory requirement date.

Channel iron

Rolled bars consisting of two flanges connected by a web. In section, it is shaped like a hollow square or rectangle with one side omitted.

Chaplet

In foundry work, a metal support which holds a core in position.

Character

One of a set of elementary marks or events which may be combined to express information. The characters normally used in numerical control include those representing the decimal digits 0 to 9, the letters of the alphabet, and special characters

Character check

A check that verifies the observance of rules for the formation of characters.

Character density

A measure of the number of characters recorded per unit of length or area.

Character font

The style of the shape of a character as distinct from its meaning. Each character has a different shape in a different font.

Character generator

That part of the display controller which draws alphanumeric characters and special symbols for the display. The process can be accomplished in hardware or software. A character is automatically drawn and spaced every time a character code is

Character recognition

As related to artificial intelligence, the ability of the machine to correctly recognize a printed or cursive character. The identification of graphic, phonic, or other characters by automatic means.

Charcoal iron

An iron which has been smelted with wood charcoal as fuel. Its freedom from sulphur results in its extremely high quality.

Chase

To cut threads on a lathe, usually with a single edged cutting tool, as distinguished from cutting threads with a die.

Chaser

A thread-cutting tool which is used on a die-head for turret lathes and screw machines.

Chasing threads

Cutting threads on a machine tool.

Chatter

Noise produced by the rapid vibration of a cutting tool against the work being machined.

Chatter marks

Imperfections on the finished surface of the material after a machining operation where vibration existed.

Check nut

Same as lock nut.

Checkpoint

A place in a routine where a dump for restart purposes is performed.

Checkpoint restart

The process of resuming a job at a checkpoint within the job step that caused abnormal termination. The restart may be automatic or deferred. Deferred restart involves resubmitting the job.

Cheek

In foundry work the middle section of a three-part flask.

Chemical dip-brazing

A process where a filler is applied to a joint, then the whole is immersed in a bath of molten chemicals, resulting in a secure adhesion of the two parts.

Chemical milling

Sometimes called contour etching, it is a method of controlled metal removal by chemicals. The workpiece is immersed in an etchant, usually a strong alkaline solution where chemical action removes the desired metal.

Chief draftsman

The person in charge of a drafting department; the connecting link between the drafting room and management.

Chief engineer

Often called the plant superintendent or plant manager, the chief engineer is in charge of all working personnel, and is held responsible by management for the efficient operation of the plant.

Chill

To surface-harden cast iron by the sudden cooling of a piece of metal or a mold.

Chilled casting

Casting made in a steel or iron mold. This type of casting is harder because of the rapid cooling of the casting by this method.

Chip

To cut or clean metal with a cold chisel. A piece of metal removed from the workpiece by a cutting tool.

Chip breaker

A shallow groove ground along the cutting edge of a tool bit to cause the chip being removed in a cutting operation to break into short pieces or to curl tightly. Used mostly on lathe operations.

Chip, integrated circuit

In the integrated circuit process, a number of complete circuit functions are formed on a slice of semi-conductor material and then separated into individual circuit functions.

Chisel

Cutting tool with a beveled edge, used for cutting, engraving, or mortising metal, stone, or wood.

Chord

A straight line connecting the extremeties of an arc; a secant; the portion of a straight line contained by its intersections with a curve.

Chordal pitch

The distance from one point on a gear tooth to the corresponding point on the next tooth, measured as a chord of the pitch circle.

Chrome nickel steel

A very difficult steel to machine, forge or heat treat, and quite expensive. Ordinarily, nickel steel or chrome vanadium steel will serve the same purpose at lower cost.

Chrome vanadium steel

An extremely tough steel, 0.87 chromium and 0.18 vanadium. It is capable of 210,000 lbs. Pressure per square inch and has a very high elastic limit.

Chromium

A grayish-white, very hard metallic element (symbol cr) used in making alloys, pigments, as a mordant, etc.

Chromium steel

A hard, tough steel, containing from 1 to 2% chromium.

Chuck

A clamping arrangement to hold a tool, as a drill, or material to be worked upon (such as a lathe). Varieties include: geared scroll chuck, sometimes called universal, planer chuck, drill chuck, tapping chuck, independent reversible jaw lathe chuck.

Chucking reamer

A reamer with three or four spiral flutes. Some types have oil passages through them.

Churning

In foundry work, the agitation of the molten metal in a mold to provide a more solid casting.

Cinder bed

A layer of cinders under a mold to help provide for the escape of gas.

Circle

A plane figure bounded by a curved line equidistant from the center at all points.

Circuit

A path that is used to direct electricity.

Circuit breakers

A safety switch which acts as a fuse and automatically opens an overloaded circuit.

Circular interpolation

A mode of contouring control which uses the information contained in a single block to produce an arc of a circle. The velocities of the axes used to generate this arc are varied by the control.

Circular milling machine

A vertical milling machine on which both the table and the cutter rotate.

Circular pitch

The distance from the center of one gear tooth to the center of the next tooth, measured on the pitch circle.

Circular saw

A metal disk with saw teeth spaced around the edge, mounted upon an arbor through the center.

Circumference

The boundary line of a circle; the distance around.

Circumscribe

To encircle. To draw lines around.

Clamp

A tool for holding parts together, made in a variety of designs.

Clamping bars

Bars used to hold parts of a mold together to prevent separation due to the expanstion of gases.

Clapper box

The toolholding device on a planer or shaper which swings freely in one direction only to prevent the tool dragging on the work on the return stroke.

Class i, tape template control

Uses a tape on which a given physical dimension is punched or indented. This dimension is equal or in proportion to a physical dimension of part. Class i  control is equivalent to the use of a rolled up template and it can describe 1 or 2 dimensions.

Class ii, machine cycle programmer control

In this type of control, the tape substitutes for mechanical or electrical cycling devices. It turns facilities off and on at the proper time, indexes tooling, activates clamping devices, etc.

Class iii, point-to-point locator control

This type of control automatically locates the table and/or the cutting tool to a numerically defined point and then cycles the operation. This control is usually described in two dimensions but is permissible to control three or more motiions.

Class iv, continuous tool path control

A system in which the cutting path results from the coordinated simultaneous motion of two or more axes. It can produce contours with three-dimensional complex curves and so-called warped surfaces, depending on how many axes are controlled

Clearance

The space between two mating parts. On a lathe tool, the angle between the cutting edge and the vertical position of the work.

Climb milling

Feeding work into the milling cutter in the same direction the cutter rotates. Not advisable for most milling operations.

Clipping

The process of determining either in hardware or in software the graphics to be displayed on a screen. As the perspective, depth or view of the picture changes, the lines that overflow the screen must be clipped off so they do not wrap around.

Clockwise

From left to right in a circular motion.

Closed circuit

A circuit that is complete and allows current to flow.

Closed shop

A shop which employs union members only.

Closed-loop system

A system in which the output, or some result of the output, is fed back for comparison with the input, for the purpose of reducing the difference.

Coating

Coating is the application of some material such as metal, organic compound, etc. To the surface.

Coaxial

Having a common axis, or coincident axes.

Cobalt

A pink-white metal of the iron group, very tough, and desirable in some cases for the blue pigments it forms.

Cobaltcrom steel

An alloy steel, suitable for cutting tools, containing 3.5% cobalt, 12.5% chromium, and 1.5% carbon.

Code

A system of signals or characters and rules for their interpretation. For punched or magnetic tape; a predetermined arrangement of possible locations of holes or magnetized areas and rules for interpreting the various possible patterns.

Code conversion

A process for changing the bit grouping for a character in one code into the corresponding bit group for the character in a second code.

Code reentrant

Computer code which is usually table driven and can be shared during the time that it is being used to process data for another purpose.

Coded-decimal code

The decimal number system with each decimal digit expressed by a code.

Coefficient

In mathematics, a number or letter put before an algebraic expression to multiply it.

Coefficient of entry

The actual rate of flow caused by a given static pressure compared the the theoretical flow at 100% efficiency.

Coefficient of expansion

The factor which expresses the change per unit length of material for each degree of temperature.

Coefficient of friction

The ratio between the weight of a body and the force required to move it horizontally over another surface.

Cogging

The reduction of ingots to blooms by forging or rolling.

Coil

A wire conductor wound on a form.

Coin

To stamp or form a metal piece in one operation, usually with a surface design.

Cold chisel

An all-steel chisel (has no handle) used to cut metal.

Cold drawn

The final operation in the production of certain metals; drawn through dies while cold.

Cold extrusion

For years, cold extrusion has been used in the manufacture of toothpaste tubes and other collapsible tubes from soft metals. A slug of metal is placed in the bottom of a closed cavity, struck sharply by a punch and the metal squirts up around the punch.

Cold heading

An operation in which metal is worked cold.

Cold rolled steel

Steel with a carbon content of from 12 to 20%. It is a product of either bessemer or open hearth furnaces, and is made in a variety of accurate sizes so that machining may, in some cases, be unnecessary. It will not temper, but can be case hardened.

Cold rolling

A process of producing steel with a smooth finish, and high tensile strenght, but with less ductility and toughness than hot roll.

Collapsing taps

A device to cut internal threads by machine, providing higher production and less thread damage. It works similarly to self-opening dies, but in reverse.

Collar

A ring around a shaft, used to inhibit motion at the end of the shaft.

Collet

A collar clutch, or clamping-piece, as for a rod; i.e., a workholding device.

Color harden

A hardening technique usually done for appearance only.

Color temper

Using the color range steel passes through when heated to determine the proper degree of hardness.

Column

A vertical support.

Combination

A group of units which may be used in various arrangements; i.e., a combination square set, consisting of a rule or blade, a square-head, center-head, and bevel protractor.

Combination chuck

A chuck on which the jaws may be operated either in unison or individually.

Combination die

A die used in power presses that both cuts the blank and shapes it (a combination blanking and drawing die).

Combination drill and countersink

See centerdrill.

Combination square

A set of tools consisting of a calibrated blade, a center head, bevel protractor and a square head with a level. Used primarily for machine layout work.

Comfort zone

The range of effective temperatures over which the majority of adults feel comfortable.

Command

A piece of information that determines which branch of an algorithm or application program will be used. Vaguely distinguishable from an instruction by being in a data stream rather than in the text or by being specified on-line rather than off-line.

Command readout

A visual display of information read from the tape of a numerical control unit.

Comment statement

An expression which explains or identifies a particular step in a routine, but which has no effect on the operation of the computer in performing the instructions for the routine.

Communication

Transmission of intelligence between points of origin and reception without alteration of sequence of structure of the information content.

Communication control character

A control character intended to control or facilitate transmission of data over communication networks.

Communication link

The physical means of connecting one location to another for the purpose of transmitting and receiving information.

Communications network

The collection of transmission facilities, network processors, etc., Which provides for data movement among terminals and information processors.

Commutation

The act of a commutator in converting generator output from a.c. to d.c.

Commutator

A mechanical device that reverses armature connections in motors and generators at the instant so that the current continues to flow in only one direction.

Compare

An operation in which two quantities are matched for the purpose of discovering their relative magnitudes or algebraic values.

Compass

An instrument having two branches or legs, usually pointed, and hinged at the top by a pivoted joint, used for taking or marking measurements, describing circles.

Compatibility

If programs can be executed on two computers without alteration, compatibility exists. A computer is said to be upwards compatible with another when a program written on the first can be executed on the second but not vice-versa.

Compensation

When contouring, compensation is a displacement, always normal to the cutting path and workpiece programmed surface, to account for the difference between the actual radius or diameter of the cutting tool and the programmed dimension.

Complement

The operation of changing the sign of a number from positive to negative or from negative to positive. A number that can be derived from a specified number by subtracting it from a specified number.

Complementary angle

One of two angles whose sum is a right angle.

Complex steel

Steel which contains more than two alloying elements.

Complier

A computer program that operates on symbolic input data to produce expanded machine instructions for handling specific tasks.

Component

A physical geometrical object which can be named and described in graphic terms and stored. A compound component is made up of two or more components, any of which may themselves be compound components.

Compound indexing

See dividing head.

Compound rest

A secondary slide, tool rest and swivel plate superimposed on the cross slide of a lathe. Usually hand-fed, the compound rest is useful particularly in the cutting of angles.

Compression

The process by which a confined gas is reduced in volume through the application of pressure, as in the cylinder of an internal combusion engine.

Computer

Any device capable of performing calculations; i.e., carrying out transformation of information. The most common types of computers are analog and digital.

Computer dependent programs

Programs written using the language or features of a specific computer.

Computer graphics

That branch of science and technology concerned with methods and techniques for converting any form of information to or from graphic representation via computer.

Computer network

An interconnection of processors for load or software sharing. A complex consisting of two or more interconnected computing units.

Computer numerical control

The use of a dedicated computer within a numerical control unit with the capability of local data input. It may become part of a dnc system by direct link to a central computer.

Computer programming language

A set of precisely defined structure and snytax (representations, conventions, and rules of use and interpretation) devised to greatly simplify communication with a computer.

Computer word

A sequence of bits treated as a unit and capable of being stored in one computer location.

Computer-aided

A process has been computer-aided when the user has a task significantly lightened because the machine can perform a useful role.

Computer-aided design

A design or drafting system whereby an operator interacts with a computer system to carry out a function. The computer serves as a calculation, storage, record keeping and formatting device, but does not make decisions.

Computer-aided manufacturing

Any manufacturing operation that is computer-aided. The effective utilization of computer technology in the management, control, and operations of the manufacturing facility through either direct or indirect computer interface with the physical resources

Concave

Hollow and rounded, as the interior of a sphere or circle; incurved; opposed to convex.

Concentration

The function of routing information from a number of communication links onto a smaller number of higher-capacity links, and providing the reverse flow from fewer to more links.

Concentric

Having a common center.

Concurrent

Pertaining to the occurrence of two or more events or activities within the same specified interval of time.

Condensation point

The temperature at which the removal of any heat will begin a change of state from a vapor to a liquid.

Condenser

A device in which the superheat and latent heat of condenstaion are removed to effect a change of state froma vapor to a liquid.

Condensing unit

The portion of refrigeration system where the compression and condensation of the refrigerant occurs.

Condition code

A code that reflects the result of a previous input/output, arithmetic, or logical operation.

Conditional jump

A jump that occurs if specified criteria are met.

Conduction

The transfer of heat from molecule to molecule within a substance.

Conductivity

The opposite to resistivity, it is the ability of a material to allow electron flow.

Conductor

Any material with the ability to permit passage of electric current. Opposite of an insulator.

Conductor stake

A sheet metal tool used to bend or shape rainspouting and similar work. It has long cylindrical ends of different diameters.

Conduit

A rigid metal or plastic tube through which wires are run.

Cone

A solid figure, circular at the base which tapers uniformly to a point at the top.

Cone mandrel

A mandrel upon which work is centered between two cones. One cone is backed against a shoulder on the mandrel, the work is centered on it, and the second cone is inserted in the other end of the work with a nut on the mandrel tightening the two cones.

Cone pulley

A one-piece pulley having two or more diameters.

Configuration

The group of machines, devices, parts, etc., Which make up a system.

Conic generator

That part of a display controller which draws circles or ellipses on the display surface.

Conjugate angle

Either of two angles whose sum is a perigon.

Consecutive

Pertaining to the occurrence of two sequential events without the intervention of any other such event.

Constant

A number used as a basis in calculations after having been deduced by actual experiment.

Constant cutting speed

The condition achieved by varying the speed of rotation of the workpiece relative to the tool inversely proportional to the distance of the tool from the center of rotation.

Contactor

A magnetic relay switch with contact points which usually open and close a high voltage circuit

Contacts

The points in a switch where circuits are made or broken.

Continuity

The description of a complete circuit through which electricity can flow.

Continuous casting

A casting technique in which the casting is continuously solidified while it is being poured. In this operation the mold dimensions need not determine the length of the casting.

Continuous data

Data of which the information content can be ascertained continuously in time.

Continuous path

A type of nc machine in which rate and direction of relative movement of machine members is under continuous control.

Contour

A continuous path operation in which simultaneous control of more than one axis is accomplished. The line bounding a figure or body; outline.

Contour control system

A system in which the cutting path results from motion of two or more axes

Contour control system

A system in which the controlled cutting path results from the coordinated, simultaneous motion of two or more axes.

Contour etching

See chemical milling.

Contouring

Also known as continuous path. The method of nc machining where the control system generates a contour by keeping the cutting tool in constant contact with the workpiece.

Contraction

In foundry work, the decrease in volumn due to cooling.

Contrast

The subjective difference in appearance of two parts of a field of view seen simultaneously.

Controller

An apparatus of unitized or sectional design, through which commands are introduced and manipulated. A program controller has the following functions: data computation, encoding, storage, readout, process computation, and output.

Convection

The motion resulting in a fluid from the differences in air density and the effect of gravity.

Conventional

Not original, customary, or traditional.

Conversational mode

Communication between a terminal and the computer in which each entry from the terminal elicits a response from the computer and vice versa.

Conversion

The process of changing from one method of data processing to another or from one data processing system to another.

Converter

A device capable of converting impulses from one mode to another, such as analog to digital, or parallel to serial, or one code to another.

Convex

Curving outward like a segment of a globe or of a circle viewed from the outside; bulging out. Opposed to concave.

Coolant

A liquid, usually composed of soluble oil and water designed to lubricate, reduce friction and heat, and permit faster production of machining operations.

Coordinate

One of a system of lines by which position is determined.

Coordinated dimensioning

A system of dimensioning where a point is defined as being a certain dimension and direction from a reference point as measured with respect to defined axes.

Copper

A reddish, ductile, metallic element (symbol cu) occurring native and in combination. It is one of the best conductors of heat and electricity and is extensively used in the arts, both in the pure state and in alloys, as bronze, brass, etc

Copper losses

Heat losses in copper coils due to resistance.

Copy

To reproduce data in a new location or other destination, leaving the source data unchanged, although the physical form of the result may differ from that of the source.

Core

That part of a mold which shapes the interior of a hollow casting. The unaffected interior of a case hardened piece.

Core box

A wooden box in which the core is rammed up in foundry work.

Core drill

A hollow drill used to remove specimens from metal for testing purposes. It drills a ring around the core which gradually fills the hollow drill. It is then necked at the base by a necking tool and removed from the hole.

Core machine

A foundry machine having a hopper with a horizontal worm at the bottom, used for making square or round stock cores.

Core oils

Oils used as binders in making sand cores. Linseed oil is common for this foundry operation.

Core oven

The oven in which cores are baked in a foundry.

Core print

A projection on a pattern which by forming an impression in the sand, locates and holds the core in position while the mold is being poured.

Core sand

Molding sand used in the making of cores.

Core wash

A mixture used for painting cores.

Coring up

Positioning cores for casting.

Corrective maintenance

Maintenance specifically intended to eliminate an existing fault.

Corrosion

The destructive breaking down of metals into their oxides or metallic salts.

Corrugated iron

Sheet iron formed into alternating concave and convex ridges and depressions.

Corundum

A very hard aluminum oxide commonly used as an abrasive.

Cosine (angles)

The quotient of the adjacent side divided by the hypotenuse.

Cotangent (angles)

The quotient of the adjacent side divided by the opposite side.

Cotter key

See cotter pin.

Cotter mill

A milling cutter used for cutting grooves, keyways, etc.

Cotter pin

A split pin which is usually inserted through a bolt or shaft and the protruding split end then spread apart. It prevents nuts or other threaded retainers from backing off.

Counter

A device such as a register or storage location used to represent the number of occurrences of an event.

Counterbalance

A weight, usually fastened to a wheel or cylinder to give it perfect balance.

Counterbore

To enlarge an end of a hole cylindrically.

Counterclockwise

From right to left in a circular motion.

Countersink

To enlarge an end of a hole conically. To cut a flaring depression into which the conical head of a screw will fit so that its face will be flush with the surface. A tool for countersinking.

Coupling (plumbing)

A fitting with inside threads only; used for connecting two pieces of pipe.

Cpu

Central processing unit. The basic memory or logic of a computer that includes the circuits controlling the processing and execution of instructions.

Cramp iron

In foundry work, a bent iron used with a wedge to clamp the drag and cope together.

Crane

A machine used for lifting heavy weights by the use of a cable, cable drum, jib, and various gears, operated either electrically, hydraulically, or by hand.

Crane ladle

In a foundry, molten metal is carried in a large ladle, when filled the combined weight makes it necessary to use a traveling crane.

Crank shaper

A shaper designed so the ram is operated by a crank motion.

Crimping machine

A machine containing grooved rolls through which sheet metal is passed to reduce one end of cylindrical work so that it will insert into the standard size end of another piece, as stovepipe or spouting.

Critical temperature

The temperature at which certain chemical changes take place in metal during heat treatment. This temperature varies with different metals.

Crocus cloth

A tough cloth used for polishing, to which pulverized oxide of iron is glued which is the polishing element.

Cropper

A machine used for cutting metal rods, etc. A shear.

Cross hairs

One type of cursor mark using intersecting horizontal and vertical lines. The intersection of the lines is the target point on the display whose coordinates are desired.

Cross section

A plane section of an object on a drawing, cut at right angles to the longitudinal axis.

Cross valve

A valve on a pipe connecting two paralled pipelines, which provides for an interchange of flow between the two lines.

Cross-feed

Transverse feed. On a shaper or planer, the feed that carries the tool across in a facing operation; at right angles to the axis of the machine.

Cross-hatching

In drafting, a system by which different kinds of lines and their arrangement will indicate which of a variety of metals is to be used. Usually on blueprint details.

Cross-slide

A dove-tailed slide on the lathe which permits transverse movement of the cutting tool assembly. Also similar devices on other machine tools such as the planer.

Crossed belt

A belt which is crossed between the driver and the driven pulley to produce a reverse direction of the driven pulley.

Crossrail

The part of a planer or boring mill which supports and permits movement of tool heads and tool slides.

Crowbar

A heavy bar of iron or steel, flat on one end, which is used as a lever.

Crown

An angular or rounded contour, as on the face of a pulley.

Crucible steel

A high grade steel used for tools, cutlery, etc. It is made by melting wrought iron in a crucible with an additive of high carbon content such as pig iron or charcoal. The finished product contains from .75 to 1.5% carbon.

Cryogenics

The study and development of extremely low temperature processes.

Cube

A solid figure bounded by six equal squares, and having all its angles at 90 . In math, a number multiplied by itself two times; see cube root.

Cube root

A number which taken three times as a factor produces a number called its cube. This 3 x 3 x 3 = 27. Three is the cube root of 27, conversely, 27 is the cube of 3.

Cubic measure

1728 cubic inches equal 1 cubic foot; 27 cubic feet equal 1 cubic yard; 231 cubic inches equal 1 u.s. gallon; 128 cubic feet equal 1 cord.

Cubical content

The volume, or the amount a vessel will hold.

Cumulative

Steadily increasing. Gathering value, volume or strength by addition or repetition.

Cup grease

A heavy-bodied lubricant.

Cup wheel

A grinding wheel designed to cut on its edge, shaped like a cup.

Cupola

A furnace for melting cast iron.

Cupro-nickel

An alloy of copper and nickel; ductile, malleable, and corrosion resistant.

Curling die

A die which makes curled edges on cup-shaped sheet metal pieces.

Current

The movement of free electrons through a conductor

Curve

A line with a continuous change of direction.

Cut gears

Gears with teeth that have been machined rather than cast.

Cutter

A cutting tool used in a machine tool for removal of metal.

Cutter compensation

Displacement, normal to the cutter path to adjust for the difference between actual and programmed cutter radii or diameters.

Cutter offset

The distance from the part surface to the axial center of a rotary cutter or to the center of a radius. The difference between the part surface and the cutter path during a machine operation.

Cutter path

The path described by a cutting tool as the part is being cut to the desired dimensions.

Cutting angle

The angle measured between the surface of the material being cut, and the face of the cutting tool.

Cutting compound

Another name for coolant.

Cutting oils

A different category from that of the coolants. Cutting oils are designed more to lubricate while coolants or cutting compounds are designed for cooling. The cutting oils are heavier, more greasy.

Cyanide

To treat with a cyanide; a chemical compound used in case hardening. Cyanide of potassium is very poisonous. In metal working it is used in the heat treatment of steels.

Cyaniding

A process of surface hardening alloys with an iron base by heating them in contact with cyanide, then quenching.

Cycle

An interval of space or time in which one set of events or phenomena is completed. Any set of operations that is repeated regularly in the same sequence. The operations may be subject to variations on each repetition.

Cycle shift

A shift in which the data moved out of one end of the storing register are re-entered into the other, as in a closed loop.

Cylinder

A solid described by the circumference of a circle as its center moves along a straight line; the ends of the solid are parallel, equal circles. A hollow, cylindrically shaped object, proportioned so that the length exceeds the diameter.

Cylindrical

Having the form or shape of a cylinder.

Damping

A means of suppressing oscillation in a system which is caused by the system's response to correction signals.

Dandelion metal

An alloy consisting primarily of lead, with smaller parts of antimony and tin. It is used as a heavy duty bearing metal.

Dardelet thread

A self-locking thread of french origin. The included thread angle is 29 . The locking action is provided by a slightly tapered root on the bolt, and a similar taper on the crest of the nut thread.

Data

A representation of facts, concepts, or instructions in a formalized manner suitable for communication, interpretation, or processing by human or automatic means.

Data base

A collection of data fundamental to an enterprise, comprised of comprehensive files of information having predetermined structure and organization and suitable for communication, interpretation or processing by human or automatic means.

Data base analyzer

A computer program that reports information on every usage of data, identifies each program using any data elements, and indicates whether the program inputs, uses, modifies, or outputs the data element.

Data base management systems

System software which controls and supervises the updating, editing, and executing of items from files in a multi-user environment.

Data block

A group of words considered as a unit, one line across the program sheet which is sufficient to command the machine slides to move from one point to another.

Data bus

A common communication line which allows coded data in a parallel or series mode to be transmitted between processors or subsystem components.

Data channel

An input/output bus which provides a path to transfer data between devices.

Data code

A structured set of characters used to represent the data items of a data elements.

Data collection

The act of bringing data from one or more points to a central point.

Data entry

Data entered by an operator from a single data device such as a card or badge reader, numeric keyboard, or rotary switch.

Data entry device

An electromechanical device to allow manual input of data to the computer system. Examples of a data entry device are: alphanumeric keyboard, data tablets, function keys, a joystick, a mouse and a trackball.

Data file

A collection of related data records organized in a specific manner; e.g., an inventory file (one record for each inventory item, showing the cost, selling price, number in stock, etc.).

Data hierarchy

A data structure consisting of sets and subsets such that every subset is of lower rank than the data of the set.

Data identifier

The means of establishing the identity of data by a classification method so that data with close resemblance can be related on a one-to-one or a category basis. Examples of identifiers are names, titles, limits or boundaries.

Data item

An individual member of a set of data denoted by a data element.

Data link

Linkage of a teletypewriter with a remote computer using public telephone lines.

Data logging

Recording of data about events that occur in time sequence.

Data management

Collectively, describes those functions of the control program that provide access to data sets, enforce data storage conventions, and regulate the use of input/output devices.

Data medium

The material in or on which a specific physical variable may represent data.

Data processing

The execution of a systematic sequence of operations performed upon data.

Data processing system

A network of machine components capable of accepting information, processing it according to a plan, and producing the desired results.

Data reduction

The transformation of raw data into a more useful form; e.g., smoothing to reduce noise.

Data set

All of the records or files pertaining to a particular application. That piece of hardware that interfaces a peripheral to a computer over a phone line.

Data stream

The flow of data to create an ordered set of information from one or more files.

Data structures

The organization of data in a computer to enable useful manipulations on the data. The organization of datum, data, or data sets into classification categories with identifiers and referencing relationships.

Datum

A point of reference.

Datum line

Any fundamental line from which graphic calculations are made.

Daubing

Plastering a cupola after heat, or to fill cracks in cores.

DC

Direct current.

Dead band

The range through which an input can be varied without initiating response.

Dead center

An accessory for the lathe and some other machine tools consisting of a steel shank tapered to fit the tailstock spindle, the other end consisting of a pointed end with an included angle of 60 . Called dead because it does not rotate.

Dead-smooth file

A file with the finest cut teeth made.

Debug

To detect, locate, and remove mistakes from a routine or malfunctions from a system.

Decarburize

To remove carbon from metals.

Deceleration distance

The calculated distance for deceleration of an axis of motion to avoid position overshoot.

Deceleration programmed

A controlled velocity decrease to a fixed percent of programmed rate.

Decimal

Pertaining to or founded on the number 10. Proceeding by powers to 10 or of one-tenth. A decimal fraction or one of its digits.

Decimal code

A code in which each allowable position has one of ten possible states. The conventional decimal system is a decimal code.

Decimal digit

One of the symbols 0 through 9 when used in numbering in the scale of ten.

Decimal equivalent

The value of a fraction expressed as a decimal.

Decode

The process of translating from a language that a computer or machine control unit can understand to one that a human can comprehend. The reverse process is called encoding.

Decoder

A device which translates data from a coded form to an analog or other easily recognized form without significant loss of information.

Dedendum

The portion of a gear tooth between the root circle and the pitch circle; it is equal to the addendum plus the clearance.

Dedicated computer

A computer devoted exclusively to a single machine or application. A mini-computer in a dnc system is dedicated to a single machine or small group of machines.

Dedicated tape reader

A single tape reader used on a single machine.

Degras

A grease used in belt dressings, also added to lubricants to increase the viscosity.

Degree

A unit of angular measurement; 1/360 part of the circumference of a circle. It is further broken down into minutes and seconds: 60 seconds equal one minute; 60 minutes equal one degree.

Delete character

A character used primarily to obliterate any erroneous or unwanted character.

Delimiter

A flag that separates and organizes items of data.

Delta metal

An alloy of zinc and copper with a small amount of iron.

Demagnetizing

The removal of magnetism

Demodulation

The process of retrieving data from a modulated carrier wave.

Density

The ratio of the mass to the volume of a specimen

Density factor

The ratio of air density with that of standard air.

Department

An administrative subdivision of a facility. It may consist of one or more work centers, and is often used to designate location and areas of responsibility or processing operations.

Depth cueing

A feature in a display system that shades vectors to make an image appear three-dimensional. The shading is done by varying the intensity of the coordinates to create depth in and out of the screen because of the projection.

Depth gage

A gage used for measuring the depth of holes and recessed portions, formed of a rule and a cross-beam and calibrated usually in fractions of an inch.

Depth micrometer

Similar to a depth gage, but capable of more precise measurements. The basic difference is its micrometer adjustment and calibration.

Depth of cut

The depth of tool engagement in a material at any given time.

Derivative action

Control action in which the output is proportional to the rate of input change.

Descriptor

In information retrieval, a word used to categorize or index information.

Design engineer

One who takes the responsibility for the engineering, specifications, economy, and efficiency of a product design.

Design language

A language similar to any language used to program a computer but structured to accommodate the terminology used in a particular design environment to which it applies.

Design rule checking

A computer program which automatically compares and signals violations of design instructions against predetermined limited conditions.

Designer

One who creates and draws the design for a product to be manufactured.

Destructive read

A read process that also erases the data in the source.

Detail

To provide specific instruction for making a part by way of drawing dimensions, notes, and complete specifications.

Detailer

A draftsman who prepares detail drawings.

Development engineer

Usually concerned with experimental work. He is expected to provide information and data for contemplated changes in a product.

Deviation

Error, variation, or departure from a standard.

Deviation alarm

An alarm caused by a variable departing from its desired value by a specific amount.

Device

Mechanical, electrical or electronic contrivance with a specific purpose.

Device control character

One of a class of control characters intended for the control of ancillary devices associated with a data processing or telecommunication system.

Diagnostic

Pertaining to the detection and isolation of a malfunction or mistake.

Diagnostic function test

A program to test overall system reliability.

Diagnostic routine

A special routine for a computer or machine control unit that is specifically designed to locate and identify errors and malfunctions when they occur.

Diagonal

A straight line passing from one angle as of a square, to another angle not adjacent. A line drawn obliquely from a datum line.

Diagram

Line drawing, mechanical plan, or outline, as distinguished from a perspective drawing.

Dial

Any graduated circular plate or face, as of a watch, clock, gage, etc. In metalworking found mostly on gages, as dial indicator.

Dial-up

The use of a telephone to initiate a station-to-station communication with a computer.

Diameter

A straight line passing through the center of a figure or body and terminated at the boundaries thereof. The length of such a line. They are thought of usually in relation to circles.

Diameter tape

A steel measuring tape, which when placed around a cylinder or round body will provide a reading of the diameter dimension rather than the circumference.

Diametral pitch

The ratio between the number of teeth on a gear and its pitch diameter. For example, if a gear has 30 teeth and the pitch diameter is 10, the diametral pitch is 3.

Diamond

A mineral of great hardness and refractive power, consisting of carbon crystallized in the isometric system under great pressure and temperature. In the metalworking trades diamonds are used to cut and grind  metal

Diamond point chisel

A cold chisel with the cutting end in a diamond shape, with one point down to cut sharp bottomed grooves.

Diaphragm

Any dividing membrane or partition. Any device supposed to resemble a diaphragm in shape, appearance, or elasticity, as the thin vibrating disk of a telephone or phonograph, or the flexible rubber sheet of a vacuum brake.

Diazo material

A slow print film which, when exposed to light strong in the blue to ultraviolet spectrum and development, forms an image.

Die

One of a pair of hardened metal blocks or plates used to cut or form a required shape. A tool for cutting external threads.

Die cavity

The hollow space inside a die where the metal solidifies to form a casting.

Die clearance

The space between the punch and the die to provide for the thickness of the metal being worked upon.

Die forging

In repetitive forging work, to secure a more uniform, cheaper, and better forging, they are made in dies. Cost of the die prohibits this practice except for large quantity production.

Die stamping

A piece formed or cut out by a die.

Die stock

The handle for holding a threading die.

Die-casting

A method of producing castings to finished size by forcing molten metal into a suitable mold. An object or part formed by die-casting.

Diehead

A device which carries the threading dies in screw-cutting machine.

Dielectric

The insulating material between the plates or foil of a capacitor.

Diesinker

A craftsman who makes dies.

Diestock

A device used to hold threading dies, having two handles for turning the die on work (as when threading bolts by hand).

Differential calculus

A branch of mathematical analysis which investigates the minute changes of constantly varying quantities when the reactions between the quantities are given.

Differential indexing

See dividing head.

Differentiator

A device whose output function is proportional to the derivative of the input function with respect to one or more variables.

Digit

Any of the numbers from 1 to 9 and zero. A symbol used to convey a specific numerical quantity.

Digital

Pertaining to data in the form of digits. Information and values expressed in discrete terms. In a digital computer such terms are generated by a combination of binary on/off or positive/negative signals.

Digital computer

A computer that uses numbers rather than physical quantities in processing data.

Digital input data

Information supplied to a machine control or director in the form of digits, quantized pulses, or some other coding elements. These data are capable of taking on only discrete values of levels.

Digital to analog converter

A device which translates digital input information to analog output signals.

Digitize

The process of optical sensing of physical surfaces (lines, points, and curves) to produce cartesian coordinate approximations of these surfaces.

Digitizer

A device which translates analog input signals to digital output.

Digitizing

The conversion of points or lines into digital data representing their position relative to a reference source point. Used to connect graphical data to digital data for computer manipulation.

Dihedral angle

The relation of two intersecting planes, as measured by the difference in direction of perpendiculars to them.

Dimension

Any measurable extent or magnitude, as length, breadth, or thickness. A factor used to characterize a term. A 2 is a term of two dimensions, counting all the exponents.

Dimension line

A line on a drawing, not a part of the view outlines, but indicating the line or part of the drawing to which the dimension has reference.

Dimension, long

Incremental dimensions whose number of digits is one more to the left of the decimal point than for a normal dimension and the last digit shall be zero; i.e., xx.xxx0 for the example under normal dimension.

Dimension, normal

Incremental dimensions whose number of digits is specified in the format classification; i.e., the format classification would be plus 14 for a normal dimension; x.xxxx.

Dimension, short

Incremental dimensions whose number of digits is the same as normal dimensions except the first digit shall be zero; that is 0.xxxx for the example above.

Dinging hammer

A hand hammer used to straighten or remove dents from sheet metal.

Dinking die

A small punch or die used to make holes in paper, cloth, leather, etc., By striking it with a hammer, or less often used in a machine.

Diode

A component with the ability to pass electricity in one direction, while limiting flow in the other.

Dip brazing

Work is immersed in molten spelter until hot enough to fuse.

Direct current

Current in which the electrons flow in one direction.

Direct memory access

An input/output system that allows peripheral devices, including other cpus, to access a computer's central storage area without help from the computer's cpu. This technique is especially common in microcomputers.

Direct numerical control (dnc)

Numerically controlled operation of a machine under direct computer control.

Disc

A storage device consisting of a number of flat circular plates, each coated on both surfaces with some magnetizable material. A number of tracks are available on each surface and data are read from or written to a track by means of read/write heads

Disc cartridge

A disc which is removable from the disc drive for interchangeability. A cartridge usually consists of a stack of individual discs.

Disc storage

A storage device that uses magnetic recording on flat rotating discs.

Discharge pressure

The pressure read at the compressor outlet.

Disconnect signal

A signal transmitted from one end of a subscriber line or trunk to indicate at the other end that the established connection should be disconnected.

Discrete

Pertaining to distinct elements or to representation by means of distinct elements, such as characters.

Dispatching

Selecting and sequencing of available jobs to be run at individual work stations and the assignment of these jobs. The act of scheduling a task for execution.

Display

A visual presentation of data on an output device.

Display data terminal

A physical device in a system at which data may be entered and/or viewed.

Display device

An output unit that gives a visual representation of data. The data is displayed temporarily but arrangements may be made for making a permanent record.

Display group

A collection of display elements that can be manipulated as a unit and that may be further combined to form larger groups.

Display menu

Options listed on a display allowing an operator to select the next action by indicating one or more choices with an input device.

Display terminal

A terminal consisting of one or more display devices and one or more input/output devices such as tablets, joystick, control balls, trackballs, light-pens, alphanumberic keyboards, function keys, and tape readers.

Display unit

A device which provides a visual presentation of data.

Distributed computer network

A collection of computers and input/output devices that can communicate with each other.

Distributed data base

A collection of data files that are stored in separate storage devices in a network. One logical data base which has been divided between physical locations within a distributed information system.

Distributed information system

A coordinated set of information-processing capabilities implemented in two or more relatively independent resource centers such as computer sites, terminal locations, and so on.

Distributed processing

A method of performing a data processing task by performing the needed calculations in a distributed computer network. By performing simultaneous operations on interconnected processors of a distributed computer network, the efficiciency is increased.

Disturbance

An undesired change in a variable, which tends to adversely affect the value of a controlled variable.

Divide

To separate into parts.

Dividend

A quantity divided or to be divided into equal parts.

Dividers

Compasses for measuring or setting off distances. Those used in metalworking have two very hard sharp metal points which scratch or scribe lines on metal surfaces.

Dividing head

An attachment for a milling machine and certain other machine tools used to measure in degrees or parts of a circle. This operation is called indexing. In simple indexing, the dividing head crank only is turned.

Divisor

That by which a number or quantity is divided.

Document

A medium and the data recorded on it for human use; e.g., a report sheet, a book. By extension, any record that has permanence and then can be read by man or machine.

Documentation

The creating, collecting, organizing, storing, citing, and disseminating of documents, or the information recorded in documents. A collection of documents or information on a given subject.

Dog

A projecting piece at the side of a machine tool worktable which trips the automatic feed mechanism to stop or reverse table movement.

Dolly blocks

Odd-shaped steel blocks used for straightening fenders and as seaming irons for other irregular shapes.

Double belting

Extra thick or two thicknesses of leather used to make belts.

Double end bolt

See stud bolt.

Double precision

Pertaining to the use of two computer words to represent a number.

Double thread

A thread with two helices winding parallel with each other around the body. Usually found on square or acme threads to provide more rapid travel.

Double-action press

A press with two rams, one inside the other, so designed that one stroke immediately follows the other, and two operations are thus performed with one revolution of the press.

Double-cut file

A file with rows of teeth crossing each other at an angle of approximately 45 .

Dovetail

An interlocking joint, which usually permits a back-and-forth sliding motion. The cross-slide on a lathe, for example, is usually dovetailed.

Dovetail cutter

Milling cutters designed to cut dovetails.

Dowel

A pin or other form of metal projection, anchored in one piece and fitting into a hole in an abutting piece to prevent motion or slipping, or to keep the pieces in their correct relative position.

Downtime

The time interval during which a device is inoperative.

Draft

The angle given a molding pattern to permit it to be withdrawn from the mold without disturbing the mold form.

Drafting

The art of drawing plans, usually with the aid of instruments.

Draftsman

One who does drafting work; prepared drawings from which blueprints are copied.

Draw

To stretch or shape metal by hammering. To temper steel by gradual or intermittant quenching of the material.

Draw chuck

A workholding device for a lathe which operates with a longitudinal motion in a tapered bearing and is used for small, accurate work.

Draw filing

A finishing operation with a single-cut file, in which the file is pulled rather than pushed in the operation.

Draw screw

A small rod with threads at one end for insertion in the threaded holes in the draw plate.

Draw-cut shaper

A shaper which cuts on the backward stroke instead of the usual forward stroke.

Drawing board

A board, usually of basswood, soft poplar, or white pine, to which a draftsman attaches his paper for drawing. It usually has battens on the back or end and provides a smooth surface for his work.

Drawing die

A die used for pressing sheet metal into cup-like shapes.

Drawing of pattern

The removal of a pattern from the molding sand in a foundry.

Drawing of temper

In heat treating, the heating of steel to red heat and permitting it to cool slowly to remove hardening or tempering.

Drawing out

Heating and hammering of metal in a forging operation to reduce the section area and increase the length.

Drawplate

A hardened steel plate having a hole, or a series of conical holes, through which wire is drawn.

Dress

To dress a tool is to restore it to original shape and condition by grinding or, sometimes, forging.

Drift

A narrow, wedge-shaped tool designed to force a drill from its socket or sleeve. Sometimes called a center key.

Drift pin

A tapered pin used to align holes in mating parts.

Drill

To cut a cylindrical hole with a drill, usually a twist drill. A pointed cutting tool rotated under pressure.

Drill bushings

Hardened steel bushings inserted in jigs or fixtures to serve as guides for drilling, usually making it unnecessary to layout or center drill the location of the hole, thus permitting more rapid production.

Drill chuck

A chuck made especially for holding drills, usually three jawed. They are often referred to as jacob's chucks, but this is a brand name.

Drill gage

A flat steel plate drilled with holes of standard drill sizes, and identified as to size, so that the size of a drill may be determined by finding the hole that a drill fits.

Drill grinding gage

A gage used to check the length and the angle of the lips of a drill.

Drill jig

A device for the rapid locating and drilling of holes in repetitive work. The jig is made to hold the work securely. Holes in the face of the jig serve as guides for a drill, which when inserted  will drill an accurately positioned hole.

Drill press

A geared, power driven machine tool used for drilling holes in metal.

Drill press vise

A small vise used for holding work for drilling on a drill press.

Drill rod

A carbon steel rod ground to accurate sizes and excellent finish, available in a large variety of sizes.

Drill shank

The end of the drill by which it is held and driven. Some drills have a shank tapered to fit into the spindle of the drill press. Some drills have a shank turned the same diameter full length (straight shank) and are designed to fit into a chuck.

Drill sleeve

A steel fitting, tapered inside and out, designed to make a drill with a small shank fit a spindle with a larger socket.

Drill spindle

The part of a drilling machine which actually holds the drill. It has vertical movement, and revolves.

Drill tang

The flattened portion on the end of a taper shank drill which prevents the drill from twisting in the socket, and permits removal of the drill from socket or sleeve with a drift.

Drill tape

A punched tape with numerical control commands for automatic hole drilling.

Drill web

The metal which separates the flutes.

Drill, back taper or longitudinal relief

Taper from point to shank to prevent rubbing while drilling.

Drill, body

The fluted portion of the drill.

Drill, body clearance

The difference in the diameter between the margin and the land. It is the relief of the drill behind the margin.

Drill, dead center

The sharp chisel edge at the point of a drill formed by the intersection of the two properly ground lips.

Drill, flute

The groove to provide cutting edges at the point, chip passage and lubrication.

Drill, helix

Angle of the flutes to the axis of the drill.

Drill, lip

The cutting edge.

Drill, lip clearance

The clearance behind the cutting edge.

Drill, margin

The narrow cylindrical ground strip along the edge of the flute.

Drill, point

Entire cone shaped surface at the cutting end of the drill.

Drive fit

Using force or pressure to accomplish the union of mating pieces.

Driver

The gear, wheel, or pulley from which power is transmitted to others called driven.

Drop forging

A shaped object formed between dies by the use of a drop hammer. The process for forging with a drop hammer.

Drop out

In foundry work, the loosening of the sand in the cope when the mold is closed.

Dross

Impurities which accumulate on the surface of molten metals.

Drum storage

A storage device that uses magnetic recording on a rotating cylinder.

Dry bulb temperature

Temperature read with an ordinary thermometer.

Dry grinding

Grinding operations which do not use a coolant.

Dry sand

Sand which has been oven-dried to provide more resistance to molten metals in foundry work.

Drying

The removal of moisture from a mold by baking, hot air injection, or heating by charcoal.

Ductile

Capable of being hammered into thin layers or of being drawn out into wire, as of certain metals, also called pliant.

Dull iron

In foundry work, iron which is not as hot as it should be for pouring.

Dump

The removal of all or part of the contents of a computer storage medium such as memory or disc and reproduce them on some other medium such as printout, tape, or cards.

Duplex receptacle

Double-outlet receptacle

Duplex steel

A low-carbon, inexpensive steel produced by the bessemer process and further refined in open hearth. It may be still further refined for better quality.

Duplicate

To reproduce exactly.

Dust

Small solid particles created by the breaking u of larger particles as a result of a process.

Dust collector

An air cleaning device to remove and collect heavy particulate from exhuast stems.

Dutch metal

An alloy of 2 parts zinc and 11 parts copper.

Dwell

A timed delay of programmed or established duration, not cyclic or sequential; i.e., not an interlock or hold. On a grinding machine, the time elapsed between the end of a table movement and the beginning of the reverse movement.

Dynamics

The branch of mechanics which is concerned with the laws of force which produce motion in bodies.

Dynamometer

An indicator for finding horsepower transmitted by a shaft

Eccentric

Deviating from the center or from the line of a circle.

Eccentric clamp

A quick-acting clamping device which utilizes the principle of the eccentric.

Eccentric fluted reamer

A reamer designed so that the concave channels are unevenly spaced. However, the flutes are exactly opposite so that micrometer readings may be taken. The design is intended to reduce chatter.

Eccentricity

The deviation of the centers of two circles from each other.

Echo check

A method of checking the accuracy of transmission of data in which the received data are returned to the sending end for comparison with the original data.

Economic order quantity

The amount of an item to be purchased or produced at a given time to minimize costs associated with ordering and carrying costs.

Eddy currents

Currents induced in the body of a conducting mass by a variation in magnetic flux.

Edging machine

A machine used in sheet metal to fold over the edges of sheet metal. It also is known as an adjustable bar folder.

Edit

To rearrange data. May involve the detection of unwanted data, selection of pertinent data, or any other process. To modify the form or format of data; e.g., to insert or delete characters.

Efficiency

The ratio between the output power and the input power.

Ejector

On a punch-press it is a collar or ring or similar piece that removes blanks from the interior of dies. Often called a shedder.

Elastic limit

The limit to which a material may be bent or pulled and still return to its former shape and proportions.

Elasticity

Refers to the extent that a metal body may be elongated by tensile stress and return to original size when the stress is removed.

Elbow

A pipe-fitting which joins two pipes at an angle.

Electric brazing

The various brazing processes in which the heat required is obtained from electric currents.

Electric drill

Usually refers to a portable hand drill powered by electricity.

Electric steel

Steel produced in an electric furnace. This process eliminates most of the sulphur and phosphorus and produces a clean, high quality metal.

Electrical discharge machining

This technique employs the disintegrating effects of an electrical arc to metal. Through precise control of electrical energy input, metal can be removed accurately, without regard to strength, structure, or hardness of the metal.

Electrochemical grinding

A rotating conductive grinding wheel serves as a negative terminal, the workpiece as a positive. An electrolyte flowing between the two carries the current and removes the fine abrasive particles on the grinding wheel.

Electrochemical machining

The controlled removal of metal by electrolytic action. Its application ranges from forming small-diameter, contoured holes to producing nongeometrical and unusual configurations in large masses of metal such as dies.

Electrode

Either of the two conducting elements through which a current leaves or enters an electrolytic cell, vacuum tube, electric arc or furnace; an anode or cathode.

Electrode holder

A device for mechanically holding the electrode and conducting current.

Electrolysis

The breakdown of two dissimilar materials caused by an electric current passing between them.

Electrolytic copper

Copper produced by electrolytic processes, mainly from sulphide ores from the western u.s.

Electrolytic grinding

Grinding with an abrasive wheel in an electrolytic bath. The electrolyte accomplishes most of the stock removal and the wheel removes the stock from the surface. The technique is applicable for difficult-to-grind, thermosensitive and thin walled material

Electrolytic iron

A high grade iron with excellent magnetic properties. It is made in an electrolytic process.

Electromagnet

A coil of wire wound on a soft iron core current applied to the coil causes the core to be magnitized.

Electromotive force

The force with which free electrons move in a conductor, measured in volts.

Electron

A negatively charged particle.

Electron metal

An alloy of magnesium, zinc, and copper much used for automobile pistons.

Electronic data processing

Data processing largely performed by electronic devices. Pertaining to data processing equipment that is predominantly electronic, such as electronic digital computer.

Electroplating

The act or process of plating metal by the use of electricity through an electrolyte containing salts of the plating metal in solution.

Electrostatic plotter

A device providing hard copy graphical and alphanumeric data on paper by means of electrostatic writing techniques.

Elongated hole

A hole which is not completely circular by reason of the inserting of a flat area. Dimensioned by giving the radii of the two halves plus the dimension of the flat area.

Embossing

Embossing is the process of raising a boss or protuberance on the surface.

Emery

A species of corundum, a natural abrasive.

Emery cloth

A strong, thin cloth to which powdered emery has been glued. It is used primarily for polishing metal and for removing small marks on the surface of metal.

Emery wheel

A grinding wheel in which emery is the abrasive material.

Emulate

To imitate one system with another such that the imitating system accepts the same data, executes the same programs, and achieves the same results as the imitated system.

Encode

To translate from an easily recognizable language into a coded language.

Encoder

A type of transducer commonly used to convert angular or linear position to digital data.

End item

End product, or the highest level of assembly shown by the bill of material.

End mill

A milling cutter so designed that it can cut both on its end or side. Made usually with two, three, or four flutes, it is more commonly used in sizes under an inch.

End of block signal

A symbol or indicator that defines the end of one block of data.

Energy

The capability of performing work.

Engage

To bring parts together to transmit power, as two gears are engaged when their teeth mesh together.

Engine

A machine or mechanism by which generated power is applied to doing work, as the steam engine or gas engine.

Engine lathe

The basic lathe used for general machine work, so named because it originally was powered by a steam engine.

Enlarger-printer

A machine which projects an enlarged image from microfilm, develops, and fixes the image on a suitable material.

Enterprise

An organization (business, governmental, educational...) Which makes use of information system resources.

Entry

Each statement in a programming system. In general, each entry is written on one line of a coding form and punched on one card, although some systems permit a single entry to overflow several cards.

Entry loss

Loss in pressure caused by air flowing into a duct or hood.

Equivalent

Quantities equal to each other but expressed in different terms.

Erase

To obliterate information from a storage medium; to clear; to overwrite.

Error

The margin by which an automatic control missed its target value.

Evaporator

A device in which a liquid refrigerant is vaporized.

Exhaust

The passage through which the spent steam of an engine cylinder is carried to a condenser or to the outer air.

Expanding mandrel

A type of mandrel or arbor for the lathe that is made to expand after inserting it in a hole or bore so as to fit tightly after installation.

Expansion fit

The inner mating piece is placed in dry ice or liquid nitrogen until the cold makes it shrink sufficiently to allow is insertion in the outer mating piece. As the piece warms, it expands and makes an extremely tight fit with its mate.

Expansion reamer

A reamer which may be expanded slightly in diameter in order to allow minor size adjustments.

Expediting

The function of searching out and correcting conditions accounting for discrepancies between planned and actual performance. The rushing or chasing of production orders which must be fulfilled in less than normal lead time.

Experimental drawings

Drawings of parts which are not to be made as a regular product of the company. They differ from shop assembly and shop detail drawings in that one sheet may contain an assembly and details, or several details on one sheet.

Explosive forming

An advanced industrial technique of exploding sheet metal into a shaped finished part. It utilizes the pressure wave generated by an explosion in a fluid to force the stock being formed against the walls of a die.

Exponent

A small symbol or number placed above and to the right of a mathematical quantity to indicate the number of times it is multiplied by itself (to be taken as a factor).

Extension tap

A tap with an unusually long shank to permit tapping in places inaccessible to a tap of standard length.

Exterior angle

Any of four angles formed on the outside of two straight lines cut by a third line. The angle formed between any side of a polygon and the extension of an adjacent side.

External thread

The thread on the outside of a bolt or screw.

Extrude

To force a plastic, metal, or other substance through a shaped opening in order to give it a desired cross-section.

Eyebolt

A bolt with an eye or hole at the end usually occupied by the head.

Ezy-out

A tool made in a variety of sizes for removing broken studs and bolts from holes.

F.P.M.

Feet per minute.

Fabrication

Work done in the shop or factory, as cutting, punching, sub-assembling, riveting, or welding rolled sections together, before delivery to the building site. Making by combining parts, assembling.

Face

To machine a flat surface on a metal piece by means of a machine tool.

Face lathe

A deep-gap lathe designed for machining large flat surfaces, usually has a very short bed.

Faceplate

A circular plate that fits on the spindle of a lathe and carries or drives the workpiece.

Facility record

A record containing data describing production facilities, such as work centers, tools, machine tools, and storage locations.

Facing

In foundry work, a mixture of sea coal and sand is placed on the pattern before the mold is rammed up; for smaller molds, talc or plumbago is used. The operation aids in producing smoother castings.

Factors

The factors of a given number are those numbers which when multiplied together give a product equal to that number, thus 2 and 3 are factors of 6 as 4 and 6 are factors of 24.

Fagot

In forging work, a fagot is a bundle of iron bars which will be heated, hammered, and welded into a single unit to form into another bar.

Fahrenheit

The most commonly used scale in the u.s. for measuring temperature in which the freezing point is 32 , and the boiling point is 212 . It is named after gabriel fahrenheit, a german physicist 1686-1736.

Family of parts

A group of like parts.

Farad

The measurement unit of capacitance.

Farmer's drill

A drill used on soft metals, differing from most drills in that it has straight flutes.

Fast pulley

A pulley which is attached to a shaft, as by a key, to transmit motion.

Fastener

A fastener is a mechanical device for holding two or more bodies in definite positions with respect to each other.

Fastening

An assembly process used for combining and holding together by means of integral or separate fasteners. Usually may be readily disassembled.

Fatigue

The tendency of metal to break under loads previously sustained, because of repeated or excessive strains.

Feather

A flat sliding key partly sunk in a shaft and partly in a hub, to guide the motion of the hub lengthwise.

Feed

On machine tools in which the work revolves, feed is the rate of travel of the tool in a cutting operation,  on machines on which the cutting tool revolves, it is the rate of travel of the work table.

Feed function

The relative velocity between the tool or instrument and the work due to motion of the programmed axes.

Feed gears

On machine tools these gears transmit motion to the feed rod and control the rate of feed.

Feed holes

Holes punched in a paper tape to enable it to be driven by a sprocket wheel.

Feed rate

A term used to quantify the rate of movement of a machine element, expressed as a unit of distance relative to time or other machine function such as spindle rotation, table stroke, etc.

Feed rate by-pass

A function directing the control system to ignore the programmed feed rate and substitute a selected operational rate.

Feed rate override

A manual function directing the control system to modify the programmed feed rate by a selected multiplier.

Feed screw

Same as lead screw.

Feedback

Information returned from the output of a machine or process for use as input in subsequent operations.

Feedback loop

The part of a closed loop system which provides controlled response information allowing comparison with a referenced command.

Feeler

A piece of steel with a rectangular cross section, hardened and ground to a standard, precise dimension.

Feeler gage

A gage composed of a number of thin leaves of steel, each accurately dimensioned as to thickness. It is used to determine the clearance between two parts.

Female

The recessed part of any piece of work into which another part fits.

Female thread

A thread cut into a hole as in a nut.

Ferrite

An iron compound used in the construction of magnetic storage devices.

Ferrous

Metals whose major ingredient is iron.

Ferrule

A ring of metal enclosing and confining the wood around the tang of an edged tool to prevent splitting.

Fibrous

Having the character of fibers, as opposed to granules, in the structure of metals.

Field magnets

Electromagnets in the field of a generator or motor.

File

A tool made of tool steel having sharp cutting points or teeth across its surface, used for abrading or smoothing other substances.

File

A repository of organized information consisting of records, items, or arrays, and data elements. A known increment of storage. Also, an unstructured or user-structured form of data storage. Often restricted to one user or one application.

File card

A flat wooden brush-like tool fitted with short, fine wires used to clean files.

File integrity

The ability to retrieve and reproduce a document without the chance of its being lost or misfiled.

File layout

The arrangement and structure of data in a file, including the sequence and size of its components. By extension, a file layout might be the description.

Fillet

A concave surface or filling at the intersection of two surfaces to provide increased strength.

Fillet weld

A weld approximately triangular in cross-section joining two surfaces at right angles to each other in a lap, tee or corner joint.

Filter

A device or program that separates data, signals, or material in accordance with specified criteria.

Fin

A thin projecting edge on a casting or other metal surface.

Fin-neck bolt

A bolt with two fins under the head to prevent the bolt from turning while the nut is being tightened. Other than the fins it strongly resembles a carriage bolt.

Fine pitch

A screw with a comparatively high number of threads per inch, or a gear with many small teeth is said to have a fine pitch, but the term is relative rather than specific.

Finish

A smooth surface produced by a fine cut on a metalworking machine or by grinding, filing, etc.

Finish allowance

In pattern making, it is the amount added to the size of the pattern to permit machining the casting down to the required size. The machining operations provide more precise dimensions and a better finish than can be obtained in the rough casting.

Finishing cut

The last cut of a machining operation, usually of shallow depth and with a fine feed, to obtain precise dimensions and smoother surfaces.

Finishing tool

A metal-cutting tool shaped and ground so that it will leave a minimum of surface irregularities on the work and used to bring the work to the final required dimension and finish.

Firm joint caliper

Calipers which have the two legs joined by a firm joint instead of a rivet.

First in first out (fifo)

A system of inventory control that designates material to be disbursed in the same order as received.

Fishtail cutter

A metal-cutting tool used mostly in vertical milling machines, designed to cut slots or grooves in shafting and not capable of heavy feeds or deep cuts.

Fit

The type and closeness of contact between two surfaces.

Fit (class of) for threads

Loose-(class i), commercial, medium-(class ii), snug-(class iii), wrench-(class iv), sweat-(class v). For non-threaded parts: slip fit, force fit, drive fit, shrink fit.

Fitting drawing

A drawing that shows a group of related parts which must be fitted before final assembly, but which are not assembled to the machine as a unit.

Fixed block format

A format in which the number and sequence of words and characters appearing in successive blocks are constant.

Fixed cycle

A preset series of operations which direct machine tool axis movement and/or cause spindle operation to complete such action as boring, drilling, tapping or combinations thereof.

Fixed sequential format

An nc tape format whereby each word in the format is identified by its position. Every word must be stated even though it is repeated from the previous block.

Fixture

A device which holds the work while cutting tools are in operation. It differs from a jig in that it has no guides, or special arrangements for guiding the tools.

Flame harden

A method of surface hardening steel by heating the metal with the flame of an oxyacetylene torch, then quenching.

Flame spraying

A process where a metal is brought to a melting point and sprayed onto a surface to produce a coating.

Flange

A projecting portion of a member for rigidness or fastening.

Flange pipe

Water or steam pipe with a flange on each end to attach it to other pipes or connections.

Flanged nut

A nut with a flange on the bottom to take the place of a washer.

Flanged pulley

A pulley with a flange on one or both of its faces to keep the belt from slipping off.

Flash

A thin fin of metal formed at the parting line of a casting or forging caused by the metal being forced out from the edges of the die. In welding, metal and oxide expelled from a joint made by resistance welding.

Flash welding

A resistance welding process wherein coalescence is produced simultaneously over the entire area of abutting surfaces by the heat obtained from resistance to the flow of electric current between the two surfaces.

Flask

A wooden or metal frame which holds the sand that forms the mold in foundry work.

Flatness

Deviation from a plane, above or below, over a complete two-dimensional area, called out as per foot and overall.

Flatter

A type of blacksmith's hammer.

Flaw

In a casting or forging, any crack or defect which may eventually cause it to fail.

Flexible coupling

A flexible connector or adapter joint between two working elements.

Flexible shaft

A shaft made of jointed links encased in flexible tubing; used to transmit power in places where a rigid shaft could not be used.

Flip

A software function which enables a graphical construction to be rotated 180 degrees about x and/or y axis. The final construction is then a mirror image of the original through a specified axis. Same as mirror image projection.

Flip-flop

A device having two stable states turned on or off, 0 or 1. A programming technique to alternate input-output devices while processing. A circuit or device containing active elements, capable of assuming either one of the two stable states

Floating tool

A tool (reamer, drill, etc.) Secured in its holder in such a manner that it may be guided in operation by the piece in which it works.

Floating zero

A characteristic of a numerical machine tool control permitting the zero reference point on an axis to be established readily at any point in the travel. The control retains no information on the location of any previously extablished zero

Floppy disk

Magnetic recording on a flexible platter.

Floturn process

Process another term for shear spinning.

Flourescent penetrant inspection

Testing technique which does not harm the metal being tested. An oil base solution is sprayed on the metal which penetrates all cracks and crevises. The surface is then cleaned and the metal inspected under a black lamp. The defects glow

Flow

A quantity passing a point per unit of time.

Flow chart

A systematic arrangement of data or procedures in graphical form that helps illustrate trends, movement, organization, comparisons, and the like. A graphical representation of the definition, analysis, or solution of a problem, in which system are used.

Fluidics

The branch of science that deals with the study and application of hydraulic phenomena to accomplish logic, data processing, control and actuation functions such as comparing, adding, negating, amplifying and differentiating.

Flute

The groove to provide cutting edges at the point, chip passage and lubrication of certain multiple-lip cutting tools as a reamer, drill, tap, etc.

Fluted reamer

A reamer which cuts at its sides, the flutes being cut longitudinally.

Fluting cutter

A milling cutter designed to cut flutes on taps, reamers, etc.

Flux

A substance that promotes the fusing of minerals or metals, as borax.

Flux density

The number of lines of flux in an area of magnetic force.

Flux-cored electrode welding

A variation of the gas shielded metal-arc welding process in which the fluxing materials are inside the formed strip.

Flycutter

An adjustable, single edge, revolving cutting tool, used to enlarge drilled or bored holes. Used mostly on drill presses and milling machines.

Flywheel

A heavy wheel whose weight resists sudden changes of speed, thus securing uniform motion in the working parts of an engine or machine.

Follow dies

Two or more punches and dies in one die body and punch holder arranged so the work is fed from one to another to complete a series of operations. Sometimes called progressive dies.

Follower rest

A support for lathe work. It is attached to the carriage opposite the tool to prevent the work from springing away from the tool.

Font

A set family or assortment of graphic symbols of a given size and style.

Foot pound

In calculating work units, a foot pound means one pound lifted one foot high.

Footstep bearing

A bearing located at the bottom of a vertical spindle or shaft to carry the end thrust.

Force feed lubricators

Plungers actuated by a cam shaft deliver a metered amount of oil to parts to be lubricated.

Force fit

Mating parts considered permanently assembled because of the tightness of the fit. Requiring force to assemble.

Foreground/background technique

Automatic execution of programs on a priority basis, allowing programs to execute when higher-priority programs are not utilizing the system.

Forehand welding

Welding in the same direction that the flame is pointing

Forge

To shape hot metal by hammering or pressing.

Forging drawing

A small drawing or sketch made to scale and containing the overall forging dimensions.

Forging press

A machine designed to produce the pressures necessary for die forging.

Forked center

A dead center designed for a lathe tailstock which has a v-head instead of a 60 degree center. It is used to hold cylindrical stock for drilling operations when the drill is mounted in the spindle and the hole is to be drilled laterally through the stock.

Format

A means, usually in an abbreviated notation, by which the motions, dimensional data, type of control system, number of digits, auxiliary functions, etc., For a particular system can be denoted.

Format detail

Describes specifically which words and of what length are used by a specific system in the format classification.

Format, input media

Physical arrangements of possible locations of holes or magnetized areas. Also the general order in which information appears on the input medium.

Forming

The operations necessary to shape metal to a desired form. It does not intentionally cut or change the thickness of the metal.

Forming rolls

A machine with three rolls adjustable to various gages of sheet metal used to form cylinders to specified diameters.

Forming tools

Tools with cutting edges shaped to produce a desired contour by plunging straight into the metal in lathe work.

Fortran

A high-level computer language mainly used for scientific purposes. Formula translating system. Any of several specific procedure-oriented languages.

Foundation bolts

Bolts used to anchor a machine to its foundation.

Foundation plate

A plate to which a machine is bolted. Sometimes called a sole plate.

Foundry

An establishment in which articles are cast from metal.

Fox lathe

A lathe used by brass workers. It has a chasing bar for thread cutting called a fox.

Fraction

A part of something.

Free bend test

Bending the specimen without using a fixture or guide.

Free carbon

In steel or cast iron, that part of the total carbon which is present in the form of graphite or temper carbon.

Free fit

When mating parts may be revolved within or around each other without excessive friction.

Free form

A computer language that enables the part programmer to describe the elements of a part in an english-like language vocabulary used in day-to-day work.

French curve

A tool used by draftsmen for drawing curved lines which are not arcs.

Frequency

The measurement of complete cycles per second of alternating current.

Friction

The rubbing together of two bodies. Resistance to motion due to the contact of two surfaces moving relative to each other.

Friction clutch

Any of various arrangements for transferring the motion of one system of parts to another by regulating the frictional contact between designated elements.

Friction drive

A drive in which motion is obtained by the frictional contact of surfaces, one being connected with the power system, the other with the transmission system.

Friction head

Is the pressure expressed in lbs./sq. In. Or feet of liquid needed to overcome the resistance to the flow in the pipe and fittings.

Friction welding

Weld in which welding heat is generated as a reult of revolving one part against anothe under heavy pressure..

Frozen iron

Iron which has cooled to a condition in which it is tool solidified to pour.

Fulcrum

The support on which,or against which, a lever rests.

Full annealing

When alloys with an iron base are heated above the critical temperature, held there for a time and then slowly cooled, it is known as full annealing.

Full range zero offset

A feature on some numerical control systems which gives the ability to introduce a dimension which will always be added to the tape command dimension which in turn results in the effect of moving the programmed zero point.

Full section

In drafting, when the cutting plane line passes through the entire part creating a section from the whole part, it is called a full section.

Full size

A drawing is called full size when the drawing has the same dimensions as the finished piece they represent. The term is usually written on the drawing.

Full thread

A screw thread which is cut properly and to its proper depth.

Fuller

A type of hammer used for forming grooves and spreading hot iron under hammer blows. It is a forging tool.

Fumes

Small solid particles formed by the condensation of vapors of solid materials.

Function keys

Data entry devices programmed to initiate or terminate a particular function or process in the graphic system. Function keys may or may not generate interruptions when depressed and/or released.

Fuse

A protective device containing a fusible link placed in series within a circuit.

Fusion

The melting together of filler metal and base metal, or of base metal only, which results in coalescence.

Fusion face

The surface of the base metal which melts during the welding process.

Fusion welding

Any type of welding using fusion as part of the process.

Fuxing point

The temperature at which metals or alloys melt and liquify.

Gage

An instrument for measuring, indicating, or regulating the capacity, quantity, dimensions, power, amount, proportions, etc., Of anything. A standard of comparison between like items.

Gaggers

Metal reinforcements for coping sand.

Gain

The amount of increase in a signal as it passes through a control system. The gain in a control system would refer to its sensitivity and its ability to raise the power of a signal to a required output.

Galvanize

To coat a metal surface with zinc as a protection against corrosion.

Galvanized iron

Iron which has been dipped in a bath of molten zinc.

Galvanometer

A meter for reading very small amounts of voltage.

Gamma rays

Electromagnetic radiation given off by a nulceus.

Gang drill or gang drilling machine

A drill press equipped with a number of spindles so that several holes can be drilled simultaneously. Useful for quantity production.

Gang milling

Using two or more milling cutters on an arbor to machine more than one surface simultaneously.

Gang tool

A lathe or planer toolholder designed to hold several cutting tools. Each tool cuts a little deeper than the one preceding.

Gap lathe

A lathe with an opening in its bed near the permanently mounted headstock, to permit a larger object to be swung; a removable section of the bed called the bridge is placed in this position for normal operation. Also called a break lathe.

Gap shears

A shearing machine for sheet metal, with a gap in the housing, which permits handling fairly large sheets in a limited space.

Garbage

A piece of information which is still in the computer memory but not relevant any more to the computing process. Unwanted and meaningless information. Erroneous, faulty, or extraneous data in a computer or nc program.

Gas brazing

A brazing process utilizing gas flame for heat.

Gas holes

Holes formed as a result of gas escaping from molten metal

Gas metal arc welding

Arc welding while blanketing the electrode and molten portions of the work in a stream of helium or argon.

Gas pockets

Cavities in weld metal caused by entrapped gas.

Gas tungsten arc welding

Arc welding using a tungsten electrode and a shielding gas.

Gases

Formless fluids which tend to occupy an entire space at a uniform density.

Gashing

A term sometimes used to describe the roughing cut taken on bevel gears when machining the teeth.

Gate

The opening where molten metal enters a mold cavity.

Gated pattern

A multiple pattern consisting of a number of duplicate patterns fastened together to permit faster production of small castings.

Gauge

A term used to describe the thickness of sheet metal.

Gauss

Unit of magnetic flux density or induction.

Gear

A toothed wheel used to transmit motion or change its direction in a mechanical assembly of gears.

Gear case

A housing for gears, usually filled with a lubricant. Sometimes called a gear box.

Gear cutters

Circular cutters designed specifically for the cutting of gears.

Gear ratio

The relation between the number of teeth on the drive gear and the driven gear.

Gear stocking cutter

A cutter designed to speed production, it does the roughing cuts quickly. The finishing cuts are done with a different cutter.

Gear train

Two or more gears connecting the driving and the driven parts of a machine.

Gear-tooth caliper

A measuring tool using the vernier method, designed specifically to measure the depth and thickness of gear teeth on the pitch line.

Geared chuck

A chuck on which the jaws operate simultaneously. Also called a universal chuck.

Geared down

A reduction of speed and an increase of power for the gear being driven as compared to the drive gear.

Geared head

Refers usually to a type of lathe which has a back gear on the headstock.

Geared shaper

A shaper on which the ram motion is obtained from a rack and pinion. A slow cutting stroke and a quick return stroke is provided by open belts for one direction and crossed belts for the other.

General drawing

Same as assembly drawing.

General processor

Also referred to as master programs. This is the program containing the basic intelligence for nc work that is stored in computer memory before individual workpiece programs can be processed.

Generate

Produce a subroutine or information field from precise parameters and instruction codes. In computing, to produce a program by selection of subsets from a set of skeletal coding under the control of parameters.

Generator

Machines that converts mechanical energy to electrical energy through magnetic induction.

Geometrical

Something which forms, or consists of regular lines, angles and curves; pertaining to geometry.

Geometrical progression

A series of terms, each term being equal to the preceding one multiplied by a factor common to all of the terms. For example, 2, 4, 8, 16, are in geometrical progression with 2 as the multiplier.

Geometry

That branch of mathematics which pertains to space and its relations, especially as shown in points, lines, angles, surfaces and solids.

German silver

An alloy of zinc, copper, and nickel.

Gib

A wedge-shaped or other piece of metal that holds another in place or adjusts a bearing, etc. Often used in machine tools to adjust mating dovetailed parts.

Gib-headed key

A key used in keyways with an open end. It may be inserted with the mating parts assembled, and has a shoulder or offset on its end to provide a surface against which a pry may be used for its removal.

Gilbert

A unit of measurement of magnetomotive force.

Gland

A small bearing which closes the mouth of a stuffing box, and through which a piston or spindle operates. Also called packing gland.

Glaze

To become glassy, take on a glaze; in reference to grinding wheels the spaces between the grit of the wheel becomes filled with metal or other particles and reduces the abrasive quality of the wheel.

Go or no-go gage

A precision ground gage with opposite ends only a few thousandths of an inch apart in size. One end is too large to fit a specified size hole, the other end fits satisfactorily.

Gouging

Cutting a groove in the surface of metal using an oxy-fuel arc cutting outfir.

Grab hook

A hook used in foundries for attaching loads to cranes or hoists.

Graduate

To mark in regular degrees of measurements, as on a scale or dial.

Graduations

The lines that indicate points of measurement

Graphic data structure

A logical scheme for ordering data. Used for graphical data stored in a computer system for subsequent manipulation and display. A data structure imparts meaning to data and provides means of access from one data element to one or more others.

Graphic language

Any language used to program a computer, which interacts with a display device. A language which describes or specifies pictures or drawings.

Graphic tablet

A rectangular planar surface, to which a coordinate point can be transmitted by identifying it with a cursor or stylus in some manner.

Graphics

Displaying information by plotting variables using any one of several ways (crt, pen plotter, etc.) To translate information to viewable symbolic form.

Graphite

A chemically inert variety of carbon with a metallic luster and an oily feel, used as a lubricant, and in the manufacture of electrodes, crucibles, lead pencils, etc. Also called black lead.

Graphitization

Forming of graphite in iron or steel either during solidification or heat treating.

Grating

Gratings provide a method of measuring from one point to another. The movement between a pickup cell and an optical grating produces variations in the intensity of light on a multiple photosensitive device. These are converted into electrical pulses.

Gravity, specific

The ratio of the mass of a unit volume to the mass of the same volume at a standard temeprature.

Gray iron

Cast iron or pig iron which has a gray, crystalline structure.

Green core

A core that has not yet been baked.

Greenfield

Flexible metal conduit for protecting wire conductors.

Grind

To remove material with a rotating abrasive wheel.

Grind finish

A finish accomplished by grinding. In most cases a smoother finish and more precise dimensions may be obtained by grinding than by cutting metal; however, it cannot remove quantities of stock as swiftly as cutting.

Grinder

A machine on which grinding work is accomplished.

Grinding

A machine operation which consists of finishing a metal surface with the use of abrasives.

Grinding stock

The amount of material left on a piece of work to permit finish by grinding. It should range from 0.003 to 0.030 inch, depending on the size of the piece and its condition after roughing operations.

Grindstone

A natural sandstone wheel against which tools are sharpened as it revolves. They are not generally used in machine shops, but are more suitable for domestic tools.

Groove weld

Welding rod fused into a joint from which the vase metal was removed forming a through at the edge of the metals to be joined.

Grooving

In machine shops, the cutting of a channel or groove; in sheet metal work, it is the finishing or grooving of a lock joint with a grooving tool.

Grooving machine

A machine used in sheet metal work to replace hand grooving.

Grooving stake

A bar containing four milled grooves of different sizes. With it and a mallet, lock seams in sheet metal may be closed without the use of a grooving tool.

Gross porosity

Holes, or globular voids in a material.

Ground

The common current return for a complete circuit to the power source.

Ground wire

A conductor connected to a groun rod, water pipe, etc. On one end and attached to an appliance on the other.

Group technology

The means of coding parts on the basis of similarities of the parts. The grouping of parts into production families based on similarities in their production so that the parts in a particular family could then be processed together.

Guard

Any of various protective or defensive devices for wearing, or for attaching to an object, as a machine or implement.

Guerin

The method of forming sheet metal where the metal is forced to conform to the shape of a male die by applying force to a confined rubber pad.

Gun lathe

A large lathe designed for the machining of large artillery pieces; i.e., the turning and boring of cannon barrels.

Gun metal

An alloy of copper and tin.

Gusset

An angular piece of iron fastened in the angle of a metal frame to give strength or stiffness.

H beam

A steel beam whose section is like the letter h.

Hacksaw

A narrow-bladed, close-toothed saw for cutting metal.

Half instruction

A machine instruction which stops the execution of the program.

Half section

In drafting, when an object is shown as if it had been cut along the horizontal and vertical center lines with either one-fourth or three-fourths removed, it is referred to as a half section.

Half-nut

A threaded block of metal which has been split to permit it to be engaged or disengaged to a threaded rod, as a leadscrew on a lathe.

Half-round file

A file which is flat on one side and curved on the other. The curved side never equals a semicircle.

Half-word

A continuous sequence of bits or characters which comprises half a computer word and is capable of being addressed as a unit.

Halved pattern

A foundry pattern made in two parts to permit withdrawal from the sand when molding.

Hammer

A hand implement with a head at right angles to the handle used for driving nails, pounding, swaging, etc. A machine as a steamor trip hammer, performing functions similar to those of a heavy hand hammer.

Hamming code

A data code which is capable of being corrected automatically.

Hand miller

A small milling machine which has no automatic feeding mechanism. Sometimes called a router.

Hand tools

Tools that may be held in the hand. In the machine shop, tools are basically divided into hand tools and machine tools.

Hand wheel

Any wheel which when operated by hand produces an adjustment.

Hanger bolt

A bolt used to attach metal parts to woodwork. It consists of a screw thread and nut on the outer end, and a lag screw on the other.

Hanging core

A core with a wire hanger imbedded in it, used to avoid a deep lift for the cope.

Hard brass

Unannealed brass used for springs, etc.

Hard copy

A printed copy of machine output in a visually readable form; e.g., printed reports, listings, documents, summaries.

Hard iron

A close-grained, light colored type of cast iron.

Hard solder

Sometimes known as spelter, hard solder is composed principally of copper and zinc.

Hard-wired

A numerical control system which handles data input, sequencing, control functions and formats by fixed and committed circuit connections. Changes can be made only by changing the physical components.

Hard-wired computer

A computer in which the operating instructions are specified by the placement and interconnection of wires.

Hardening

Heating and quenching iron based alloys to produce a degree of hardness above that of the untreated metal.

Hardenss testing

Techniques used to determine the hardness of heat-treated steel.

Hardfacing

Filler material placed on a surface to increase resistance to abrashion, corrosion, and wear.

Hardware

The mechanical, electronic, and physical units and elements which make up a system.

Hardy

A square shanked chisel which in normal use is inserted in the hardy hole of smith's anvil.

Hardy hole

A square hole in an anvil into which the square shank of the hardy is inserted.

Hatchet copper

In sheet metal work, a soldering copper shaped like a hatchet.

Hatchet iron

A type of soldering iron used by plumbers.

Hatchet stake

A tool used by tinsmiths to bend sheets of tin.

Hay rope

A rope made of hay which is wrapped around a core bar in foundry work, and forms a porous mass through which gasses may escape.

Heading tool

A tool used in forging to shape the heads of bolts.

Headless setscrew

A setscrew with a screwdriver slot in the end instead of a head for wrenches.

Headstock

On a lathe, that part which contains the spindle and the power transmission unit.

Heart cam

A heart-shaped cam which changes rotary motion into reciprocal motion.

Heat

Molecular energy of motion.

Heat

In foundry work, a heat is the charge in a cupola; the metal being reduced to a fluid state.

Heat affected zone

That part of the base metal altered by heat from welding, brazing or cutting.

Heat conductivity

Speed and efficiency withwhich heat energy moves through a material.

Heat loss

Energy loss due to the resistance of a conductor or a coil.

Heat tinting

Using heat to color a metal surface through oxidation.

Heat transfer

The three methods of heat transfer are convection, conduction, and radiation

Heat treatable alloys

Alloys that reach maximum strength by heating and quenching.

Heat treatment

A variety of methods using cycles of heat and sudden cooling to change the characteristics of metals in order to obtain desired conditions.

Heat-checking

Crazing of a die surface, subjected to alternating heat and cooling

Helical

Pertaining to or shaped like a helix.

Helical gears

Gears which have teeth cut at some angle other than a right angle to the gear face. They operate more quietly and smoother than spur gears and have two teeth engaged at all times.

Helical spring

A compression-type spring shaped like the frustum of a cone.

Helium (he)

Inert, colorless, gaseous element used as a shielding gas in welding operations.

Helix

A line, thread, wire, or the like, curved into a shape such as it would assume if wound around a cylinder; a form like a screw thread.

Helix angle

An angle made by the helix of a thread at the pitch diameter with a plane perpendicular to the axis.

Henry

The unit of measurment of inductance.

Heptagon

A plane figure with seven sides and seven angles.

Hermaphrodite caliper

An instrument similar to a caliper, but with one divider leg, and one caliper leg. Used primarily for layout work.

Herring-bone gear

A gear on which the teeth slope both ways from the center line on the gear face (having, in one gear, the characteristics of both a left- and a right-hand spiral gear) and used often for heavy mining machinery.

Hertz (hz)

A unit of frequency equal to one cycle per second.

Hexagon

A figure with six sides and six angles.

Hexagonal head

A shop expression referring to the many types of six-sided bolts and screws.

Hexagonal nut

The common six-sided nut.

Hidden lines

Line segments that would be obscured from view when projecting a three-dimensional object.

Hidden surface line

On a blueprint or drawing, a line consisting of short dashes which indicates a hidden surface. Also called hidden lines, invisible edge lines.

High carbon steels

A general term applied to steels suitable for making cutting tools. They generally contain 0.50% carbon or better and have good hardening qualities.

High energy forming

The use of pneumatic-mechanical, electrical or explosive energy to form metals.

High speed steel

An alloy containing tungsten or molybdenum much used for making cutter bits, and superior to ordinary carbon steel tools.

High spots

Areas to be taken down by scraping or grinding in order to obtain a more nearly flat surface. In bench work, the work surface is often covered with a thin layer of blue dye and a precision-finished plate rubbed over it.

Hob

A specialized gear cutting machine designed to cut gear teeth on a continuous basis. Also the cutting tool used for cutting gear teeth.

Hobbing

Cutting gear teeth with a hob.

Hogging

A term used in machine shops in reference to heavy cuts.

Hoke blocks

Precision blocks used to check gages, etc. Designed by major hoke.

Hold

An untimed delay in the program, terminated by an operator or interlock action.

Hold time

The length of time force is applied to electrodes in resistance welding, after current is turned off.

Holographic storage

Information storage of a manner similar to microfilm in that the data is stored on film. The interference pattern is recorded rather than the data per se.

Holography

Method of producing three-dimensional pictures through the use of laser beams.

Home position

A fixed location in the basic coordinate axes of the machine tool. Usually the point at which everything is fully retracted for tool change and so on.

Homologous

Having a similar structure, proportion, value, or position. Proportional to each other.

Hone

To sharpen or dress with a hone. A stone or fine grit, used for sharpening cutting instruments or for obtaining a very smooth finish on a metal part.

Honing

A process used to produce an extremely fine surface finish on an object after the grinding operation. Honing permits a closer fit on critical parts.

Hood

A shaped inlet designed to capture contaminated air and condust it into and exhaust system.

Hook bolt

A bolt which has the unthreaded end bent at right angles to the bolt, or u-shaped. It has no head.

Hook rule

A rule that has a projecting piece at right angles to the blade on one end.

Hook spanner

A type of spanner wrench designed for round nuts notched on their periphery.

Hooke's law

In engineering, a law that states that within the elastic limit, the deformation produced is proportional to the stress.

Horizontal

Parallel to the horizon; on a level.

Horizontal boring mill

A machine tool for large work, with a horizontal spindle which has longitudinal and vertical movement. The work table has latitudinal movement. There is a rear post support for the arbor. On some machines the table may also be swiveled.

Horizontal drill press

A drill press with a horizontal spindle.

Horizontal milling machine

A milling machine with a horizontal spindle. The work table has feed mechanisms and may move up and down, side to side, and in and out.

Horizontal position

Weld performed on a horizontal seam at least partially on a vertical surface.

Horn

Arm of a resistance welder that carries the current and applies pressure.

Horn center

A small, transparent disk of horn used by draftsmen to place the points of their compasses upon when describing circles so that the compass point will not penetrate the paper.

Horning press

A machine used to close the side seams on sheet metal receptacles, etc.

Horsepower

The standard unit of power rating. In mechanics, one horsepower is equivalent to 33,000 pounds of lifted one foot in one minute.

Host computer

The host computer is that part of the hardware which processes interrupts and data from the various satellite intelligent terminals, or data-entry devices. Display list creation and updating can be accomplished in the computer.

Hot forming

Operations performed on metal while it is above the recrystallization temperature.

Hot shortness

Weakness of metal which occurs in the hot forming range.

Hot working

Shaping of metal at a temperature and rate which does not cause strain hardening.

Hot-die steel

Steel used in forging dies which come into contact with red-hot metal.

Hot-rolled

A term applied to commercial steel which has been rolled while hot.

Hotbox

A general term to describe overheated bearings.

Housing

A general term usually referring to castings which serve to contain, or cover working parts of machinery.

Hub

The central part of a wheel such as the part into which the spokes are inserted.

Humidity, absolute

The weight of water vapor per unit volume.

Humidity, relative

The ratio of the actual partial pressure of the water in a space compared tot he saturation pressure of [ure water at the same temperature.

Hydraulic

Denoting machines and structures that operate by means of water or other liquid under pressure; for example, hydraulic press, etc.

Hydraulic bronze

A term applied to cast bronze or brass of the type used for pump parts, valves, etc.

Hydraulic nut

A recently developed nut containing a hydraulic system which when activated locks the nut firmly in place. No wrench is necessary. Manufactured currently under the name jerry jet-nut.

Hydraulic press

A press which is operated by water power using hydraulic principles.

Hydraulics

The science of the laws of motion of liquids and their practical applications.

Hydrochloric acid

A principal product of the action of sulphuric acid and salt, it has a wide use in industry; i.e., a flux for soldering and for the removal of rust from metal. Usually used in diluted solution.

Hydrodynamics

The branch of mechanics which pertains to the laws of hydraulics.

Hydroforming

Forming parts in rubber with accurately controlled fluid pressure over a movable male die in a flexible diaphragm.

Hydrogen embrittlement

A low ductility condition in metals as a result of the absorbtion of hydrogen.

Hydrospinning

Same as shear spinning.

Hyperbola

A curve obtained by passing a plane through a cone parallel to the cone's axis. A conic section.

Hypotenuse

The side of a right-angled triangle opposite the right angle.

Hysteresis

The difference between the response of a unit or system to an increasing signal and the response to a decreasing signal.

Type Caption for New Topic Right Here

(New topic text goes here.)Abbreviation for inside diameter.

Ideal time

That part of available time during which the hardware is not being used. The time during which a machine or operator is nonproductive because of lack of work.

Idler gear

A gear placed between two other gears to transfer power without changing the direction of rotation.

Image

An exact duplicate array of information or data stored in or in transit to a different medium.

Impact energy

Amount of energy that must be exerted to fracture a part.

Impact strength

Material's ability to resist shock.

Impact test

The testing of material for resistance to shock.

Impedance

The total opposition to flow of ac resulting from resistance and reactance.

Implicit curve

A curve represented by an equation between the coordinates, not solved for either in terms of the other; for example x2 + y2 = a2.

Impurities

Undesirable elements or compounds in a material.

In-process inventory

Product in various stages of completion throughout the factory, including raw material that has been released for initial processing and completely processed material awaiting final inspection and acceptance as finished product.

Inch of water

A unit of pressure equal to the pressure of a one inch column of water at a standard temperature.

Inches of mercury

Atmospheric pressure is equal to 29.92 inches of mercury

Inclusions

Inclusions are particles of nonmetallic impurities contained in material.

Incomplete fusion

Less than complete fusion of the weld material with the base metal.

Incomplete joint penetration

Lack of fusion between metals appearing as dark lines.

Incomplete penetration

Incomplete root penetration or failure of two weld beads to fuse.

Increment

The amount which a varying quantity increases between two of its stages.

Incremental data

In computer graphics, the values that are added or subtracted from previously established coordinates to obtain new coordinates.

Incremental dimension

A dimension expressed with respect to the preceding point in a sequence of points.

Incremental feed

A manual or automatic input of preset motion command for a machine axis.

Incremental system

A control system in which each coordinate or positional dimension, both input and feedback, is taken from the last position rather than from a common datum point, as in an absolute system.

Indentation

Depression left on the surface of the base metal after welding.

Indentation hardness

Degree of resistance of a material to indentation.

Independent chuck

A chuck (workholding device) on which the jaws may be moved independently of each other.

Indexing

A method of dividing a circle into desired divisions with the use of a dividing head or indexing head.

Indicating

To align an object by means of an indicating gage.

Indicator

A gage that exhibits visually the variations in the uniformity of dimensions or contour, the amount of variation being indicated by a level or graduated dial.

Indirect cost

Cost which is not directly incurred by a particular job or operation. Certain utility costs, such as plant heating, are often indirect. An indirect cost can be either fixed or variable.

Indirect materials

Raw materials which become part of the final product but in such small quantities that their cost is not applied directly to the product. Instead, their costs become a part of manufacturing overhead.

Induced current

The current flow caused by an induced voltage.

Induced voltage

The voltage induced in a conductor or coil as it moves through a magnetic field.

Inductance

The opposition to a change in current in an electric circuit.

Induction brazing

A type of electric brazing. The heat is obtained from an inducted current.

Induction hardening

Process of quench hardening a metal using heat generated from electrical induction.

Induction motor

An ac motor with field windings energized by out of phase currents.

Inductive load

The load on a source of alternating current which will cause the current to lag voltage.

Inductive reactance

Force which opposes flow of alternating current through a coil.

Inductosyn

Trademark for farrand controls resolver, in which output signal is produced by inductive coupling between metallic patterns in two glass members separated by a small air space. Produced in both rotary and linear configurations.

Inert gas

A gas which does not normally combine chemically with the base or filler metal.

Information processing

The physical and logical operations which support the definition, establishment, and use of computer-executable application procedures (programs).

Infrared rays

Heat rays coming from both the arc and the welding flame.

Ingot iron

Low carbon, mild steel, prepared by open hearth or bessemer steel-processing operations.

Inhibiting signal

A signal that prevents an operation from taking place.

Inline processing

The processing of data in random order, not subject to preliminary editing or sorting.

Input

Transfer of external information into the control system.

Input/output (i/o) device

Input devices include consoles, typewriters, card readers, tape readers, etc. Output devices include consoles, typewriters, card punches, tape writers, printers, etc.

Inscribe

To write or imprint in some permanent way (as an inscription on a tombstone). In drawing it means to draw one figure within another, i.e., a square within a circle.

Inserted tooth cutter

A milling cutter on which the teeth may be mounted independently and be replaced individually, so that the entire cutter need not be replaced when the teeth become worn or broken.

Inside thread

An internal thread; one cut on an inside diameter, as the thread in a nut.

Inspection

The checking of finished parts to determine if they have been made to specifications.

Inspection bench or table

A bench with metal or granite top of precise smoothness and flatness, used by inspectors to check the accuracy of finished work.

Inspection by attributes

Inspection where the unit or product is classified simply as defective or non-defective with respect to a single requirement or set of requirements; e.g., go or no-go gaging of dimensions.

Inspection by variables

Inspection where a specified quality characteristic on a unit or product is measured on a continuous scale; e.g., pounds, inches, etc., And a measurement is recorded.

Inspection gages

A variety of gages, either of standard or special design, used to check the accuracy of finished work.

Inspector

One whose duty is to check finished operations or finished products in reference to accuracy and appearance. He usually has the authority to reject work which he feels has not met specified requirements.

Instruction storage

Storage media containing basic machining instructions in coded form.

Insulation

A material for covering wires or components to prevent short circuits and shock hazards

Intaglio

Engraving cut into the surface of wood, metal, etc. As opposed to engraving in relief (cameo).

Integral

All parts of a unit considered as a whole, parts which may not be separated from a unit, and collectively are considered a unit.

Integral calculus

A branch of mathematics which is involved with areas and lengths of curves, volumes and surfaces of solids, mean value, moments of inertia, and probability.

Integrated circuit (ic)

An electronic circuit that is packaged as a single small unit.the circuits vary in complexity and function from simple logic gates to microprocessors, amplifiers, and special devices.

Intelligent robot

A robot which can decide its behavior by itself through its sensing and recognizing capabilities.

Intelligent terminal

A terminal which has local processing power. It is not usually programmed by the user, and differs from a satellite in being connected using asynchronous procedures, being of lower cost, and being simpler in nature.

Interactive

Processing of data on a two-way basis, and with human intervention providing redirection of processing in a predetermined manner.

Interactive graphics

The use of interactive computer displays with graphical input/output devices.

Interchangeable

Refers to a part that has been made to specific dimensions and tolerances and is capable of being fitted in a mechanism in place of a similarly made part.

Interchangeable gear

A gear so designed that it will mesh properly with any other gear of the same pitch.

Interface

A shared boundary. An interface might be a hardware component to link two devices or it might be a portion of storage or registers accessed by two or more programs. The medium by which two separate elements are joined.

Intergranular corrosion

Corrosion occurring, primarily between grains or in the edges of the grain of a ferrous metal.

Interior angle

One of the four angles formed between two straight lines cut by a third line. The angle formed in the interior of a polygon by two adjacent sides.

Interlock

To prevent a machine or device from initiating further operations until the operation in process is completed.

Interlock bypass

A command to temporarily circumvent a normally provided interlock.

Interlocking

Parts fastened together by dovetails and other similar methods.

Intermediate gear

A gear between the driving and the driven gears.

Intermittent gear

A gear which has teeth on part, but not all, of the circumference. When the teeth are in mesh, the driven gear turns; when the plain surface between teeth are in contact, the driven gear is stationary resulting in an intermittent motion.

Intermittent weld

Joining two pieces and leaving sections unwelded.

Internal gear

When a gear engages with teeth set in the internal circumference of a ring, it is known as an internal gear. The opposite of a spur gear.

Internal grinder

A grinding machine designed for the accurate grinding of precise internal work inside cylinders, bores, holes, etc.

Internal thread

Same as inside thread, also called female thread.

Interpolation

The passing of a curve or surface precisely through the data points. The insertion of intermediate information based on assumed order or computation.

Interpolator

A device for defining the path to be followed, and the rate of travel of a cutting tool or a machine tool slide or element, when supplied with a coded mathematical description (linear, parabolic, circular, etc.) Of the same.

Interval

In shop work, the period of time between similar mechanical operations.

Inventory control

The technique of maintaining stockkeeping items at desired levels, whether they be raw materials, work-in-process, or finished products.

Inversion

A program subroutine in which a pattern is rotated about an axis and located in one or more positions.

Inverted file

In information retrieval, a method of organizing a cross-index file in which a keyword identifies a record. The items, numbers, or documents pertinent to that keyword are indicated.

Investment casting

A process that involves making a pattern surrounding it with a material and then burining away the pattern.

Involute

Complicated by reason of the intertwinings or interrelation of parts or elements. In geometry, the curve traced by a point on a line as the line unrolls from a fixed curve.

Involute gear

A gear whose tooth design is developed after the involute system as distinguished from the cycloidal system. The cycloidal type is very seldom used.

Involute teeth

Gear teeth shaped the same as the involute curve. Most common type in use today.

Ion

Atom or a group of atoms positively or negatively charged.

Ionization

Adding or removing electrons from atoms or molecules to create ions.

Iron

A metallic element obtained from ores in combination with other substances. It is sold commercially as wrought, cast, malleable, and steel.

Iron-carbon diagram

Diagram which shows the critical temperature for steel and cast irons with vaying amounts of carbon.

Irregular polygon

A polygon of unequal sides and angles.

Isometric

A form of drawing which resembles a picture more than a view.

Isosceles

Pertaining to or designating a triangle having two sides of equal length.

Izod test

Impact strength test made by striking the piece with a measured downstroke of a pendulum. And measuring the resulting upward swing.

Jack

Any of a number of mechanical devices for lifting heavy loads for short distances with a minimum of manual power.

Jack

Small screw jack used to level and support work on the worktable of planers, milling machines, etc.; Also called leveling jacks.

Jackscrew

Small screw-type jacks for leveling work in jigs.

Jam nut

Same as lock nut.

Jarno taper

One of several standard tapers used on machine tools, having a taper of 0.600 inch per foot.

Jarring machine or jolting machine

Machine used in foundries for ramming molds.

Jetnut

See hydraulic nut.

Jib

The swinging boom of a crane.

Jib crane

A crane which has a swinging boom.

Jig

A fixture for locating, holding the work, and guiding the cutting tool in operations such as drilling, reaming, counterboring, and countersinking.

Jig boring machine

A machine designed to locate and bore holes in precision parts. It resembles a vertical milling machine but is constructed with greater precision, and table movements may be controlled to within 0.0001 of an inch.

Jig bushing

A hardened-steel bushing for insertion in the face of a jig to serve as a guide for drills.

Jig, drill

See drill jig.

Jo block

Rectangular shaped blocks used as standard gages, made in a variety of degrees of accuracy, but a typical tolerance would be plus or minus 0.000002 (two millionths) inch for accuracy and 0.000003 inch for flatness and parallelism.

Job shop

A term applied to a machine shop which has no standard product. Often contracts to perform certain machining operations, usually after competitive bidding has taken place. Job shops are usually staffed by 5 to 100 employees.

Job ticket

A labor claim entered by an operator frequently in the form of a handwritten report or a punched card.

Jog

A control function which provides for the momentary operation of a drive for the purpose of accomplishing a small movement of the driven machine.

Joint

Where two pieces are joined in an assembly.

Joint efficiency

Strength of a welded joint expressed as a percentage of strength of the base metal.

Joint penetration

Depth of weld metal and base metal fusion in a welded joint.

Joule

A unit of energy equal to one watt-second.

Joystick

A data entry device used to manually enter coordinate values in special x-, y-, and z-input registers. The device consists of a vertically mounted stick or column which can be moved and twisted.

Jumper

A length of wire or a conductor used to make temporary connections.

Junction box

A metal box where two or more wire connections may be made and protected.

K capacity

K comes from the french kilo meaning thousand. An 8k computer has eight thousand bytes of processing capacity or memory in which information is stored and processed.

Keep's hardness test

A technique for testing hardness of metals, in which a standard steel drill is caused to make a definite number of revolutions, while it is pressed with standard force against the specimen to be tested.

Kennedy key

Two square-bodied keys positioned so that their diagonal corners intersect the circumference of the bore. Used for heavy work.

Kerf

The slit or groove produced in a piece of stock by a saw or cutting tool.

Key

A bar, pin, or wedge used to secure an object to a shaft to prevent relative movement between the two pieces.

Key seat

The groove which holds the key in position, as in a shaft.

Key, center

A center key is the same as a drift.

Keyboard, program

An arrangement of keys or buttons used to communicate with the computer associated with a display. Each key, when activated, causes the computer to perform some preprogrammed operation.

Keyhole

Welding technique in which concentrated heat penetrates a workpiece leaving a hole at the leading edge of the weld.

Keypunch

A keyboard-actuated device that punches holes in a card to represent data.

Keyway

A groove or slot cut into a hub to provide clearance for a key.

Killed steel

Molten steel which has been left in the furnace or ladle until the gas has escaped and the metal is quiet.

Kilo

Prefix meaning one thousand times.

Kilogram

One thousand grams. The equivalent of 2.204 pounds.

Kilometer

One thousand meters; 0.62137 mile; 3280 feet, 10 inches.

Kilopascal

Unit of pressure

Kinematics

In the field of physics, the study of laws which regulate the actions of bodies in motion.

Kinetic energy

Energy possessed by a moving body by virture of its motion.

Kink

A term applied to an angle or bend made in a piece of metal by a blow or excessive strain.

Kit

In most trades, a term applied to a tool box.

Knee

On a column and knee type milling machine, the knee is the unit that supports the table and saddle.

Knocked down

Term applied to a complete product with its parts unassembled.

Knockout pin

A pin in the base of the forming die which controls the length of the shank during forming and then ejects the formed part from the die.

Knoop (hardness test)

The knoop hardness test is applicable to extremely thin metal, plated surfaces, exceptionally hard and brittle materials, and very shallow carburized or nitrided surfaces. The knoop indentor is a diamond ground to an elongated pyramidal form.

Knuckle joint

One in which the forked end of a rod is connected by a pin to an eye (hole) at the end of another rod.

Knuckle thread

A thread useful only for rough work. It is half round at both the bottom and the top of the thread, with tolerances large enough that it can be cast in a mold.

Knurl

To roughen or indent a turned surface, such as a knob or a handle, to produce a better hand grip.

Knurling tool

A special tool used for knurling operations. It is similar in appearance to a tool holder, but contains two hardened steel rolls (knurls) with diagonal grooves cut into the faces.

Lacing

Rawhide thongs used to fasten together the ends of belts for machinery. Lacing has been generally replaced by metal fasteners used in a manner similar to staples.

Lack of fusion

Defect in a weld caused by lack of union between the base metal and the weld metal.

Ladder diagram

A diagram that shows actual component symbols and the basic wirint configuration of a relay logic circuit.

Ladle

Metal receptacle used for removing, transporting and pouring molten metal into foundry molds. They vary in shape and capacities range from 25 pounds to 100 tons.

Lag screw

A heavy wood screw with a square head designed to be used with a wrench instead of a screwdriver.

Laminated construction

Work built up in layers, as wood in pattern making. It provides more strength with less weight.

Land

The space between flutes on drills, reamers, etc. The metal left in the grooves or flutes of taps, drills, etc.

Land oil

A cutting oil made from animal fats. It is often mixed with mineral oils that improve the lubricating qualities.

Language

A defined group of representative characters or symbols with rules necessary for their interpretation and application. When applied according to the rules, a language is meaningful to a computer, nc system, or data processing devices.

Language processors

Computer programs used to translate high-level or symbolic instructions into a computer-oriented code capable of being executed by a computer.

Language translator

A general term for any assembler, compiler, or other routine that accepts statements in one language and produces equivalent statements in another language.

Lap

A soft metal surface impregnated with fine abrasive for use in polishing operations. To finish by polishing with a lap.

Lap joint

Joint in which the edges of the two metals overlap.

Lap weld

A weld made on edges that have been thinned down so that the finished weld will be no thicker than the parts welded.

Lap-riveted joint

A joint formed when two plate edges are to be joined together, and are overlapped and secured by a row or rows of rivets.

Lap-seam welding

A welding technique in which the parts to be welded are overlapped instead of butted together.

Lard oil

A cutting oil made from animal fats. Its lubricating qualities are often improved by mixing it with mineral oils.

Last in first out (lifo)

A system of inventory control that designates material be dispersed in the reverse order as received. Compare with fifo.

Lathe

A machine for shaping articles in which an object is mounted and rotated, while a tool is thrust against the work, shaping it down, usually to some circular form.

Lathe bed

The part of the machine upon which all the working parts rest. Usually made of cast metal.

Lathe center grinder

A small grinding machine which may be attached to the lathe and used for grinding centers, etc. Often referred to as a dumore, in spite of the fact that dumore is a trade name.

Lathe chuck

A holding device for lathes made in a variety of designs. It grips and holds the workpiece during machining operations.

Lathe dog

A device for clamping work so as to transmit power and motion from the spindle to the work; used when the work is mounted between centers.

Lathe tool

Often called cutting tool or bit. It is ground to the desired shape and is made from high-speed steel, stellite, and cemented carbides, usually. Carbon steel tools, once widely used, are not heat-resistant enough for today's production.

Lathe, engine

See engine lathe.

Lathe, gap

See gap lathe.

Law of magnetism

Like poles repel each other. Unlike poles attract

Layer

Weld metal thickness made of one or passes.

Layout

A laying-out or planning, as of a piece of work. In most metalworking trades, the scribing of lines, and center-punching of points and boundaries on the material to be machined to serve as a guide for the machining operation.

Layout bench or table

Similar to inspection bench.

Layout drawing

A drawing made to develop the initial design of the machine or part.

Lead

Electricity-carrying wire from the power source to the ground clamp or electrode holder.

Lead

Distance a nut will advance on a thread in one revolution.

Lead hammer

A hammer which has a head made of lead to avoid bruising or marking the material it is used on.

Lead hole

A hole drilled in a piece of work to assist the finishing drill in accurately locating the hole, and to facilitate the removal of stock when the finished hole is large.

Lead time

Projected time between placement of an order and availability of the product.

Leader

The section of tape which appears ahead of and after a section of coded tape. When producing leader by punching tape-feed, sprocket holes are produced. It may also include a parity code.

Leading zeros

Redundant zeros added to the left side of a number to fix the position of the decimal point.

Leadscrew

A long, precision threaded rod on the front of a lathe that transmits motion from the power unit to the carriage. The rate of motion may be controlled by levers on the quick change gear box.

Leather fillet

A strip of leather glued in the angles of foundry patterns to eliminate sharp edges in the sand, and make the castings stronger.

Led (light emitting diode)

A device that gives off light when current passes through it.

Left-hand thread

A thread cut in the opposite direction from the usual. To engage it, it must be turned from right to left (counterclockwise).

Left-hand tool

Term applied to lathe cutter bits, when the cutting edge of the tool is on the right side, therefore, the tool travels from left to right in operation.

Leg of fillet weld

Distance from the point where the base metals touch to the toe of the fillet.

Letter-size drills

Drills whose sizes are identified by letters ranging from a to z. The diameters are between the standard fraction sized drills, and range from 0.234 inch for a to 0.413 inch for z.

Level

See track.

Lever

A rigid bar which turns upon a fulcrum or an axis.

Leverage

The mechanical advantage gained by the use of a lever.

Library

A collection of information available to a computer, usually on magnetic tapes or discs. A collection of organized information used for study and reference. A collection of related files.

Lifter

A molder's tool used for lifting loose sand from molds. Sometimes called a cleaner.

Light cut

In machine work a cut is said to be light when the cutting tool penetrates the work to a very shallow depth.

Limit gage

A gage made to check a specified dimension. It has two openings, one made to the upper limit of the dimension, the other made to the lower limit.

Line shaft

Shafting which consists of several lengths coupled together.

Line welding

A resistance welding process wherein coalescence is produced by the heat obtained from resistance to the flow of electric current through the work parts held together under pressure by electrodes.

Lineal foot

A unit of measurement meaning 12 inches in length as distinguished from a square foot or cubic foot.

Linear

Pertaining to or of the nature of a line.

Linear interpolation

A mode of contouring control which uses the information contained in a block to produce velocities proportioned to the distance moved in two or more axes simultaneously.

Lip

A term applied to the cutting edge of a single point tool in machine shop work.

Liquidus

Lowest temperature at which a metal or alloy is compleely liquid.

Live center

A center which revolves. When a center is placed in the headstock spindle of a lathe and revolves, it is called live.

Live spindle

A spindle which revolves. On a lathe, the headstock spindle revolves and is known as a live spindle. The tailstock spindle does not revolve, and is called a dead spindle.

Load

A power-consuming device or component that resists flow.in programming, to enter data into storage or working registers. In production control, the amount of scheduled work ahead of a manufacturing facility, usually expressed in terms of hours of work.

Loaded wheel

A grinding wheel is said to be loaded when it has absorbed particles from the material it is grinding, and the grit of the wheel becomes glazed and less abrasive.

Loam

A mixture of clay and sand used in molding, is known as loam in foundry work.

Loam molds

Molds mainly used for large castings, made of brick and plastered with loam, are called loam molds.

Lock nut

A nut constructed so that it automatically locks itself when screwed tightly against another to prevent slackening.

Lock washer

A washer whose action is similar to that of a compression spring. Useful in preventing a nut from backing off because of vibration, etc.

Lockout switch

A switch provided with a memory, which protects the contents of designated segments from alteration. A device which prevents power from being applied to a machine.

Logic

The science which deals with basic principles and applications of truth tables, switching, gating, etc.

Logoff

The procedure by which a user ends a terminal session.

Logon

The procedure by which a user begins a terminal session.

Long dimensions

Incremental dimensions whose number of digits is one or more to the left of the decimal point than for normal dimensions and the last digit shall be zero; i.e., xx.xxx0.

Long ton

2240 pounds.

Longitudinal

Running lengthwise. When referring to the longitudinal motion of a milling machine table; for example, it would be the motion from left to right, or vice versa.

Longitudinal section

In drawing, a section taken through a part lengthwise.

Loop

A sequence of instructions that is executed repeatedly until a terminal condition prevails.

Loose dowel

In pattern making, it is a dowel made so it may be easily removed or replaced, not a tight fit.

Loose fit

In reference to a thread, it would be a class 1 fit, where accuracy is not required.

Loose pulley

One of a pair of pulleys which runs when the shaft it is mounted on does not. When the shaft is to run, the belt is shifted to the other pulley of the pair, known as a fast pulley.

Loss

The dissipation of energy without accomplishing work.

Lot size

A quantity of material or items to be produced at a given time.

Low carbon steels

Steels containing less than 0.30% carbon. These can be case hardened, but not tempered.

Lower explosive limit

Explosibility of a gas or vapor at ordinary temperatures expressed in percent concentration of vapors in air.

Lubricant

Almost anything used to overcome friction and permit free motion of parts. The most common are oils, grease, and graphite. Liquid lubricants are sometimes used on cutting tools in operation to reduce heat, provide better finish, and wash away chips.

Lug

A projecting piece through which something is attached, bears on, or passes.

Machinability

The characteristic of a material that describes the ease or difficulty of machining it.

Machinability index

The table that indicates the degree of ease or difficulty of machining a material. It is based on the machining characteristics of a common steel (aisi b1112 = 100).

Machine

A device for transferring or changing energy.

Machine control unit

Synonomous with numerical control system in its hardware form, sometimes referred to as the controller.

Machine drawing

A mechanical drawing of a machine or machine parts, which includes dimensions and other information necessary for its manufacture.

Machine drilling

Drilling with the use of nonportable power driven machines.

Machine independent

An nc program is said to be machine independent if it can run on another machine without alteration.

Machine language

The set of symbols, characters, or signs, and the rules for combining them, which conveys to a computer instructions or information to be processed.

Machine molding

Production of castings with the use of special machines used in the preparation of the molds.

Machine screw

A term applied to a variety of screws in common use.

Machine tap

A tap designed to be driven by power machinery instead of manually.

Machine tool

The name given to machines which as a group have the ability to reproduce themselves. A power driven machine not portable by hand, used to shape or form metal by cutting, impact, pressure, electrical techniques, or a combination of these processes.

Machining

Operations performed on metal by machine tools.

Machinist

A person skilled in the use of machine tools and the production of machined parts. Also called machine hand.

Macro

A group of instructions that are organized as a group and can be called as a unit.

Macro-etch

Chemical removal of a metal surface to make details stand out.

Macrograph

Photographic or graphic reproduction of the surface of a prepared speciman which has been magnified.

Macrostructure

Physical makeup or structure of metals revealed under amagnification of less than ten power.

Magnaflux

A nondestructive inspection technique which uses a magnetic field and magnetic particles to locate flaws in materials.

Magnaglo

See fluorescent penetrant inspection. For use on magnetic materials only.

Magnalium

An alloy of aluminum and magnesium. It is lightweight, strong, and can be easily machined, forged, or cast.

Magnesium

A lightweight metal usually alloyed with other metals for commercial use. It is used for many airplane parts, and because it ignites easily, is also used in fireworks, etc.

Magnet steel

Steel used for permanent magnets, usually crucible tungsten containing some manganese and chromium.

Magnetic chuck

A device which holds iron and steel work on its face by magnetic attraction. Used extensively on surface grinding machines and used only with direct current.

Magnetic disc

A flat circular plate with a magnetic surface on which data can be stored by selective magnetization of portions of the flat surface.

Magnetic disc storage

A storage device or system consisting of magnetically coated metal discs.

Magnetic drum

A right circular cylinder with a magnetic surface on which data can be stored by selective magnetization of portions of the curved surface.

Magnetic tape

A tape with a magnetic coated material on which data can be stored by selective polarization of portions of the surface. A tape of magnetic material used as the constituent in some forms of magnetic cores.

Main shaft

A line of shafting which is directly connected to the power source.

Major axis

The long diameter of an ellipse.

Major diameter

The largest diameter of a thread measured perpendicular to the axis.

Make-up air

Air supplied to a space to replace air exhausted or otherwise removed.

Malleable

Capable of being forged, hammered or rolled without damage to the metal.

Malleable iron casting

A casting toughened by annealing.

Malleableizing

The process of annealing white iron to remove carbon or to temper it.

Mallet

A wooden hammer.

Mandrel

A shaft or spindle on which an object may be fixed for rotation.

Mandrel stake

A long stake used in sheet metal work. It has a round face on most of its length, but terminates in a flat anvil.

Manganese

A hard, brittle, metallic element (symbol mn), grayish-white in color with a tinge of red. It rusts like iron, but is not magnetic; manganese forms an important component of certain alloys, such as manganese steel.

Manifold

Pipe or cylinder with several inlet or outlet fittings.

Manometer

An instrument for measuring pressure.

Mantissa

The decimal or fractional part of a logarithm.

Manual

An instructional book, usually containing many formulae and tables. Work done manually, by hand, as distinguished from work done by machines.

Manual backup

A method of control, in which final control elements are manually adjusted in the event of a primary system failure.

Manual feedrate override

Enables the operator to change the feed rate should the program rate be incorrect for the particular piece of material being machined. This can be done on a percentage basis on some machines or a completely new introduction of a feed rate.

Manual mode

A method of operation where data is entered manually by dial or other means instead of by program. A machine may be entirely program controlled, it may have certain functions which are done manually or it may be entirely a manual operation.

Manual programming

Opposed to automatic programming.

Manuscript

A form used by a part programmer to organize his work-piece machining instructions. From this a program tape is punched or a computer program is prepared.

Mapp

Stabilized methylacetylene-propadiene fuel gas.

Maps

Fuel gas methylacetylene-propadiene - stabalized.

Marform

A drawing process to form sheet metal using a rubber padded ram and a movable steel punch.

Marking machine

A machine used for stamping and identifying informational data on metal products; i.e., patent numbers, dates, manufacturers identification on guns, cutlery, etc.

Martensite

Very hard and brittle form of steel.

Mass production

The manufacture of an article in large quantities with the use of specialized machinery.

Master gage

Any type of gage that is used to check the accuracy of other gages. It is often built to a greater degree of accuracy than the so-called working gages it is used to check.

Master taper

Used as a gage. A master taper is used to check other tapers for accuracy.

Master workman

A worker of more than average skill, often in supervisory positions. Master mechanic is often applied to shop foreman, etc.

Match plate

Pattern equipment which consists of two plates which form the matching halves of a pattern.

Material

Same as stock.

Material control

The function of maintaining a constantly available supply of raw materials, purchased parts and supplies that are required for the production of products.

Material requisition

An authorization which identifies the type and quantity of materials to be withdrawn from inventory.

Materials planning

The planning of requirements for components based upon requirements for higher level assemblies. The production schedule is exploded or extended through the use of the bills of materials and the results are netted against inventory.

Maul

A heavy mallet.

Maximum

Refers usually to the largest size tolerated; if a dimension were given as .500 + .003, the maximum dimension would be .503.

Mean

An average. An intermediate value between two or more values.

Measuring machine

A term applied to large bench-type measuring instruments, often electronically operated, and capable of a high degree of precision.

Measuring tape

A steel or linen tape, graduated for linear measurements and ranging in length from 3 feet to 100 feet.

Mechanic arts

Term usually given to school courses in the various metalcrafts.

Mechanical drawing

A drawing accomplished with the use of instruments. Blueprints are included in this category.

Mechanical engineer

One who is knowledgeable in the design, construction and use of mechanical devices and operations. Usually a college graduate with a comprehensive mathematics background.

Mechanical properties

Those properties of a material that reveal the elastic and inelastic reaction when force is applied, or that involve the relationship between stress and strain; for example, the modulus of elasticity, tensile strength and fatigue limit. Th

Mechanics

The branch of science that is concerned with the effect of force upon matter.

Median

The middle.

Medium fit

Class 3. It is a fit that allows motion between mating parts, but not looseness. A closer fit than free fit.

Medium force fit

A tight fit, requiring strong pressure to fit one part into the other: class 7.

Mega

The prefix meaning one million times.

Megapascal

One million pascals.

Melting point

The temperature at which a solid turns into liquid.

Melting zone

The portion of the cupola above the tuyeres where the metal melts.

Memory

See storage medium.

Memory dump

A printed listing of the selected contents of a computer's storage. This is a useful, but rather costly, debugging device; from a memory dump one may sometimes deduce what caused a collapse of a routine.

Mensuration

The branch of mathematics pertaining to measurement. The process of measuring.

Merchant bar

Refined bar iron.

Mercury manometer

Used to measure vacuum in inches of mercury.

Mesh

The proper engagement of gears to transmit power.

Metal arc cutting

Method of cutting metal with an electric arc.

Metal dip brazing

A dip-brazing technique in which the filler metal is obtained from a molten metal bath.

Metal pattern

In foundries, metal patterns are reproduced from wooden ones, and these provide durability wooden ones could not.

Metal powder cutting

Oxygen cutting process which cuts metal using a powder to improve cutting.

Metal spinning

The process by which thin, malleable metals are made to assume dish-like shapes through pressure applied against them while in rapid rotation in the lathe.

Metal spraying

Wire fed through a hydrogen-oxygen flame where it is atomized and sprayed on a metal part, either as a protective coating or to build up worn places that can be remachined to size.

Metal-arc welding

Arc welding in which the filler metal for the weld is supplied by the electrode.

Metallizing

In plastics, it is the covering of the plastic with a thin layer of metal; in machine shops the term is sometimes applied to metal spraying.

Metallography

Scientific study of the constitution and structure of metals.

Metallurgy

The art or science of extracting a metal or metals from ores, as by smelting, reducing, refining, alloying, electrolysis, etc.

Metric gear

A gear designed according to the metric system of measurement.

Metric system

A decimal system of weights and measures based on multiples of ten. It is used universally in scientific work, but was first used in france.

Mho

The unit of measurement of conductance.

Micro

The prefix meaning one millionth of.

Microfilm

A fine-grain film containing an image greatly reduced in size from the original. The recording of microphotographs on film.

Micrometer

A device attached to measuring instruments to permit preciseness in adjustment or measurement.

Micrometer caliper

A calibrated measuring tool designed for precise measurements, and composed of five basic parts: barrel, sleeve, frame, anvil, and spindle.

Micromicro

The prefix meaning one millionth of one millionth

Micron

A unit of length, the thousandth of one millimeter.

Microprocessor

A large-scale-integration device that performs the functions of the central processing unit of a computer. The microprocessor is usually small in size.

Microsecond

One millionth of a second.

Mil

One thousandth of an inch (0.001).

Mild steel

A steel alloy of very low carbon content, free-cutting.

Mill

To shape or dress metal by means of a rotary cutter on a milling machine. A term sometimes applied to a building or complex of buildings where manufacturing processes take place.

Mill file

A single cut file, used for draw filing, lathe work, etc. It can range in cut from coarse to dead smooth.

Milli

The prefix meaning one thousandth of.

Milling

The process of operating any type of milling machine.

Milling machine

A machine tool that makes use of a rotary cutter to remove metal.

Millisecond

One thousandth of a second.

Millwright

A mechanic who installs machines. The term is sometimes used interchangeably with rigger.

Minimum

Refers usually to the smallest size tolerated; if a dimension were .500 - .003, the minimum dimension would be .497.

Minor axis

The smallest diameter of an ellipse.

Minor diameter

The smallest diameter of a screw thread measured across the roots and perpendicular to the axis. Also called root diameter.

Mirror-image programming

A feature of some machine control units that provides for the reversing of all instructions programmed for a specific axis (usually x) by means of a switch. This means that a single program can produce two mirror-image parts.

Miscellaneous function

An on-off function of a machine such as spindle stop, coolant on, clamp.

Mists

Small droplets of materials that are suspended in air.

Miter gears

Bevel gears with the teeth set at 45 angles to transmit power to shafts at right angles to each other. The two gears with 45 angles make an included angle of 90 . Pairs are of equal diameter, pitch, and number of teeth.

Mixing chamber

Part of the welding torch where the welding gases are mixed prior to combustion.

Mnemonic symbol

One chosen to assist the human memory such as mpy for multiply.

Modern

In data transmission, a modulator/demodulator device which converts data from one form to another for equipment compatability.

Modulus of rupture

In a bend or torsion test, the stress at which the fracture occurs, expressed as a constant.

Mohs' scale

A scale for grading the hardness of minerals. It ranges numerically from a hardness of 1 for soft talc to a hardness of 10 for diamond.

Moire fringe pattern

The movement between a pickup cell and an optical grating utilizes the moire fringe influence to produce variations in intensity of light on a multiple photosensitive device; see grating.

Mold

The form in which a desired shape is reproduced, as in a foundry.

Molder's rammer

A wooden tool used in a foundry, wedge-shaped at one end and cyindrical at the other. Workmen use it it pack sand around the pattern.

Molding sand

Sand used in the making of molds in a foundry.

Molybdenum

A metal used in alloy with steel to produce high speed steel cutting tools. Also used in cast alloys. Often shortened to moly by workmen.

Mond or mond seventy alloy

A nickel-copper alloy with a very high tensile strength.

Monel

A copper-nickel alloy with a small amount of cobalt and iron. It is nearly noncorrosive and is used to make chemical equipment, cooking utensils, etc.

Monitor

Software or hardware that observes, supervises, controls, or verifies the operations of a system.

Monkey wrench

An adjustable wrench named for its inventor, thomas monkey.

Monobloc

Made or cast in one piece.

Monomial

A single algebraic term.

Monotron

With this instrument, a diamond ball impressor point ¾ mm in diameter is forced into the material to a depth of 9/5000 of an inch and the pressure required to produce this constant impression indicates the hardness.

Mordant

Any substance, such as tanic acid or aluminum hydroxide, which by combining with a dyestuff to form an insoluble compound (lake) serves to produce a fixed color in a textile fiber. The corrosive used in etching.

Morse taper

A standard taper used on drill presses and lathes consisting of a taper of 5/8 inch per foot.

Motion

Rapid traverse or feed direction selection, where required.

Motive power

The source of energy which activates a machine.

Motometer

A speedometer or speed counter.

Motor

A device which converts electrical energy to mechanical energy.

Motor load

Any device driven by a motor.

Motor starters

Resistive devices placed in series with d.c. motor armatures to prevent drawing of excessive current until full speed is developed.

Muck bar

When the boom is passed through muck rolls in the manufacture of wrought iron it is known as a muck bar. It does require further refining to be useable.

Mule pulley stand

An arrangement of pulleys which permits power to be transmitted to a shaft at right angles to the drive shaft.

Multimeter

A combination meter for reading voltage, amperage, and ohms.

Multipart bearings

Three or more bearing sections in a housing used for heavy duty installations.

Multiple die header

A heading machine in which the work, instead of remaining in a single die, is indexed through a series of dies. All punches usually work at once, and a part normally is finished and ejected from the last station at each stroke.

Multiple-impulse welding

The making of spot, projection and upset welds by more than one impulse of current. When alternating current is used, each impulse may consist of a fraction of a cycle or a number of cycles.

Multiple-projection welding

A projection welding process in which two or more separate welds are made in parallel, simultaneously.

Multiple-spindle

A machine tool with more than one spindle (multiple-spindle drill press).

Multiple-stroke headers

A heading machine similar to the single stroke former, but in which the work remains in the die as it is subjected to blows from a second or third punch to form severe heads or extrude the shank more than is possible with a single blow.

Multiple-threaded screw

A screw with two or more threads around its body. This type of screw will impart a more rapid motion than a single-threaded screw.

Multiplexing

The division of a transmission facility into two or more channels.

Muntz metal

An alloy of approximately 40 parts zinc and 60 parts copper, used mainly for ship sheathing.

Mushet steel

An alloy used mainly for cutting tools, capable of taking heavy cuts on hard metal. It contains carbon, tungsten, and manganese.

Music wire

An extremely tough carbon steel wire used to manufacture springs.

Nanosecond

One billionth of a second.

National coarse thread

Refers to the number of threads per inch of length for the commonly used diameters in the u.s. the same specifications were in use and once known as united states standard thread.

National fine thread

Once known as the s.a.e. thread (society of automotive engineers). The national fine thread is the same as the national coarse except that it has a greater number of threads per inch.

NC

Abbreviation for the national coarse series of screw threads

Neat's-foot oil

An oil used mainly for softening leather. One synonym of neat is bovine, and neat's-foot oil is obtained by boiling the hooves of cows, etc.

Neck

A narrower part of a shaft. Also to make a groove around a shaft, usually at a change of diameter, or near the end.

Necking

Machining a groove around a cylindrical shaft.

Necking tool

A lathe cutting tool designed to cut necks in shafting and other metal parts.

Needle bearing

A roller bearing in which the rollers are so thin that they resemble needles.

Nema type 1

General purpose enclosure

Nema type 10

Enclosures which meet mine safety and health administration 30 c.f.r. part 18.

Nema type 11

Enclosure for indoor use primarily to provide a degree of protection against the corrosive effects of liquids and gases.

Nema type 12

Dust-tight and drip-tight enclosure for industrial use.

Nema type 12k

Knockout are provided only in the top or bottom walls or both. They shall meet drip, dust and rust-resistance design tests.

Nema type 13

Enclosures for non-hazardous dust, lint, falling dirt and dripping noncorrosive liquids.

Nema type 2

Drip-tight enclosure

Nema type 3

Dust-tight, rain-tight and sleet-(ice) resistant-outdoor

Nema type 3r

Weather-resistant (rain and sleet proof)

Nema type 3s

Enclosures for windblown dust, rain, sleet, external icing and rust-resistance design tests.

Nema type 4

Water-tight and dust-tight enclosure

Nema type 4x

Water-tight and dust-tight enclosure with corrosion resistant material

Nema type 5

Dust-tight enclosure

Nema type 6

Enclosure for indoor or outdoors, temporary subersion, external icing and rust resistance.

Nema type 7

Enclosures for hazardous locations (class i, groups c and d)

Nema type 8

Enclosures for hazardous locations (class ii, groups e, f and g)

Nema type 9

Class ii, group e, f or g—indoor hazardous locations.

Neutral

Neither positive nor negative.

Neutral conductor

The grounded third wire in a three-wire system.

Neutral flame

Flame resulting from combustion of a perfect mixture of oxygen and welding gas.

Neutron

An electrically neutral particle.

New sand

Sand that has not as yet been used for molding.

Newton

Metric unit of force.

NF

Abbreviation for the national fine series ofscrew threads

Nibbler

A machine used for cutting odd shapes from sheets or plates of metal.

Nichrome

The trade name for a chromium-nickel alloy. It is used considerably for resistance devices such as electric heater units. It machines and welds easily.

Nickel

A hard, ductile, malleable, silver-white metallic element (symbol ni) of the iron-cobalt group: widely used in metallurgy and the arts.

Nickel plate

A thin layer of nickel deposited on the surface of objects by electrolysis.

Nipple

A short length of pipe threaded on both ends.

Nipple chuck

A rapid-adjusting chuck used for holding pipe while threading and cutting nipples in production work.

Nitriding

A method of casehardening ferrous alloys by the absorption of nitrogen at high temperatures. Quenching is not necessary.

Nixie light or tube

A glow lamp which converts a combination of electrical impulses into a visible number.

Noble metal

A term applied to precious metals or to metals that do not oxidize readily in open air.

Nodular cast iron

Cast iron containing primary graphite which is in a ball or globular form rather than flakes.

Noheet metal

Lead hardened with sodium which has good anti-friction properties, sometimes called tempered lead.

Noise

Random electrical impulses similar to radio static, occurring within the control system, which can disturb its normal operation.

Nomenclature

A list of names or terms common to any art or science. Sometimes used to refer to the individual parts of any one thing; i.e., lathe nomenclature, the names of all the individual parts of a lathe.

Nominal

The specified size (the named size), not the size plus or minus some tolerance.

Noncorrosive flux

A flux which will not cause corrosion when used for brazing or soldering.

Nondeforming steel

A steel used for tools and dies, containing up to 1.5% manganese. It is an oil hardening steel.

Nondestructive testing

Testing for defects using techniques which do not damage or destroy the part.

Nonferrous

Metals which contain no iron.

Nonpressure welding

Welding processes which do not use pressure. Sometimes called fusion welding.

Nordberg key

A round key used to lock a shaft to a hub. It is slightly tapered (1/16 inch to the foot). For large sizes the large diameter of the key is about 1/5 the diameter of the shaft. For smaller sizes (below 6 inch) the large diameter is about ¼ the diameter

Normal dimensions

Incremental dimensions whose number of digits are specified in the format classification. For example, the format classification would be plus 14 for a normal dimension; x.xxxx.

Normalizing

Heat treatment of steel to improve grain and structure, performed by heating it above its critical temperature and then cooling in air.

Normally closed

Refers to switch contacts if they are normally closed when the switch is in a non active state.

Nose

The end of tools, etc., Which is more directly involved with the operation; i.e., the chuck end of a lathe spindle, the sharpened end of a cutting tool, etc.

Notch brittleness

Tendency of a material to break at points where stress is concentrated.

Notch sensitivity

Measure of the extent of reduction of strength in a metal after notching.

Notching

A process using the notching machine, which includes the use of dies. The operation removes excess metal prior to forming or drawing, removes contoured sections from a blank, and other operations preparatory to forming or drawing.

Nozzle

Device which directs the shielding media or gas.

Number sized drills

Drills whose sizes are identified by numbers ranging consecutively from 1 to 80. Their diameters lie between the standard fraction sized drills and range from 0.228 inch for #1 to 0.0135 for #80.

Numerator

In a fraction, it is the numberal above the fraction line, which indicates the number of fractional parts taken.

Numerical control

The technique of controlling a machine or process utilizing command instructions in symbolic form which are converted into automatic servo-mechanism control.

Numerical control center

The combination of nc machines, equipment, manpower, skills, and facilities to provide a complete capability.

Numerical data

Data in which information is expressed by a set of numbers or symbols that can only assume discrete values or configurations.

Nut

A small block of steel which has internal threads. It is usually square or hexagonal in shape and usually made to specifications.

Nut arbor

An arbor used to mount nuts for machining.

Nut machine

A machine designed to produce nuts from bar steel. It will drill, thread and cut off.

Oblique

Differing from a right angle; either acute or obtuse. Neither perpendicular nor horizontal; slanting.

Oblong

Rectangular shaped; having greater length than breadth.

Obtuse angle

An angle greater than a right angle.

Octagon

A plane figure with eight sides and eight angles.

Octahedron

A solid figure bounded by eight plane faces.

OD

Abbreviation for outside diameter.

Odd-leg calipers

Calipers with both legs curved in the same direction. Used to measure shoulder distances, etc.

Odontograph

An instrument for correctly laying out gear teeth.

Off center

When two circumferences or more do not have the same center or axis; eccentric.

Off-time

In resistance welding, it is the time that one or both electrodes are separated from the parts welded.

Offline operation

Peripheral equipment which operates independently of a central computer. Just the opposite of online.

Offset

A displacement in the axial direction of the tool which is the difference between the actual tool length and that established by a programmer.

Offset surface

A surface defined in terms of some other surface by a displacement of each point dependent on the local shape.

Ohm

The unit of measurement of the resistance to flow of current through a conductor.

Ohm's law

The mathematical relationship between amperage, voltage, and resistance. (aperage is equal to voltage divided by resistance)

Ohmmeter

A meter for measuring resistance in ohms.

Oil cup

A small container for oil with an adjustable valve for releasing the contents, and a glass cylinder where the flow of oil to the bearing below may be visually observed.

Oil groove

A narrow, semi-circular groove cut into the face of a brass bearing or on sliding surfaces to provide for the distribution of lubricants.

Oil hardening

Using a mineral oil to quench hot metals during heat treatments.

Oil hole

A small hole for the admission of oil to a bearing.

Oil-hole drills

Drills which contain oil holes running from the shank to the lip to permit oil to be released at the end of the drill to provide lubrication and wash out chips. Gun drills and other deep-hole drills are usually equipped this way.

Oiling collar

A collar used on high speed shafting which runs in a reservoir of oil, carrying the oil and spreading it on the journal.

Oilless type bearings

Usually are bronze bearings with graphite inserts. Others are made with a porous oil-absorbing metal, and require oiling at long intervals. The warmer the bearing, the more oil is released.

Old man

A term applied to a frame or support to assist in manual drilling jobs which are not done on drilling machines.

Omnigraph

A machine which permits a number of similar plates to be cut by aceteylene torches at the same time. A pointer which follows a template or pattern directs the path of the cutting tips.

On center

The placing of centerlines in line.

Open hearth

A reverberatory type of steel-making furnace.

Open loop system

A system which generates output signals but relies on the integrity of the system to execute them. There is no feedback for monitoring or comparing purposes.

Open mold

A perfectly level bed of sand is built up and the pattern placed on it and rammed up. Used for large flat work, plates, etc., Without using a flask.

Open shop

A shop where both union and nonunion employees may be working. Distinguished from the closed shop where it is necessary to belong to a trade union to be employed.

Open side planer

A planer which can accommodate a workpiece wider than the bed of the machine. This is accomplished because there is an upright carrying the rail on one side of the machine only.

Open washer or slip washer

A flat washer with a slot or opening on one side so that the washer may be slipped over the bolt without completely removing the nut, or sliding it over the bolt to a position under the head.

Operation code

An alphanumeric code that identifies a specific operation; e.g., 040 for milling, 050 for drilling, 070 for deburring, 090 for inspection, etc.

Operator

A machine operator capable of production work on a machine tool, but usually not having the training and background of the journeyman machinist.

Optical pyrometer

Temperature measuring device

Optical reader

Mechanism reading punched tape optically by detecting light falling through punched holes.

Optimize

The rearrangement of instructions or data in nc or computer applications to obtain the best balance between operating efficiency and best use of hardware capacity.

Optional stop

A miscellaneous function command similar to a program stop except that the control ignores the command unless the operator has previously pushed a button to validate the command.

Order control

Control of the progress of each customer order or stock order through the successive operations in its production cycle.

Order number

A number assigned by production control to a given order in the shop.

Order point

The inventory level such that if the total stock on hand plus an order falls to or below the order point, action is taken to replenish the stock.

Ordinate

In math, the distance of any point from the axis of abscissas, measured on a line parallel to the axis of ordinates in a coordinate system. The line or number indicating such a distance.

Orifice

A small opening into a cavity.

Orthographic

Pertaining to right lines or angles.

Orthographic projection

A projection in which the lines lie at right angles to the plane of projection.

Oscillation

A fast back-and-forth movement; a vibration. Fine finishes or high polishes are sometimes obtained by a device which oscillates fine abrasives on the work.

Out-of-round

Variations of the distance from the true center of an object to the circumference.

Output

The finished result of an activity. Data that has been processed from an internal storage to an external storage. Opposite of input.

Outside caliper

A caliper designed to measure outside diameters or dimensions.

Outside corner weld

Fusing two pieces of metal together with the fusion taking place of the outer part of the seam.

Oval

An egg-shaped figure.

Overall

A term used in reference to the longest dimension of a drawing or piece of work.

Overhead position

Weld on the underside of joint with the face of the weld in a horizontal position.

Overhead shafting

Shafting suspended from the ceiling. No longer in common use in machine shops, at one time it was the standard method of transmitting power from the power unit to a number of machines.

Overlap

Extension of the weld face metal beyond the toe of the weld.

Overlays

The number of passes through a computer required to process a complete task or program.

Overload

A load on a component or circuit which exceeds design specifications.

Overshoot

Occurs when motion exceeds target value.

Overwrite

To record into an area of storage so as to destroy the data previously stored in the same area.

Oxidation

Combining of a substance with oxygen.

Oxidizing

A method of finishing metal work with the use of an acid solution.

Oxidizing flame

Flame produced by an excess of oxygen in the torch mixture.

Oxyacetylene

A mixture of acetylene and oxygen gas for welding purposes. This method is widely used in industry, as it can produce one of the hottest flames for welding operations.

Oxyacetylene cutting

Oxyfuel gas cutting process which uses a flame and a jet of oxygen to cut metal.

Oxyacetylene welding

Method of oxyfuel gas welding in which oxygen and acetylene are combined and burned to to provide heat for welding.

Oxyfuel gas cutting

Cutting metal using an oxygen jet and a preheating flame .

Oxyfuel gas welding

Method of welding which combines and burns oxygen and a fuel gas to create the heat required for welding.

Oxygen cylinder

Specially built container manufactured to icc standards and used to store oxygen.

Oxygen lance cutting

Oxyfuel gas cutting process which heats base the base metal and blows away molten metal with a jet of oxygen.

Oxyhydrogen flame

Chemical combining of oxygen with hydrogen gas

Oxypropane gas flame

Chemical combining of oxygen with lp gas

Pack-harden

To carburize and then to case harden.

Packing

The material packed around a piston rod to prevent leakage. It is enclosed in a stuffing box.

Pad

A shallow projection. It differs from a boss only in that its surface is closer to the main body.

Pad lubrication

An oil saturated pad used for lubrication.

Panel box

A fuse and switch box from which branch circuits are distributed.

Pantograph

An instrument used for copying drawings, either on an enlarged or a reduced scale.

Pantometer

An instrument for measuring elevations, angles, etc.

Paper tape reader

A device that senses and translates the holes in perforated tape into electrical signals.

Parabola

A conic section or curve such as would be made by passing a plane through a cone parallel with its side.

Parabolic interpolation

A high order of interpolation producing contoured shapes by having the cutting tool travel through parabolas or portions of parabolas. This method of interpolation is particularly applicable to mold or die work.

Parallax

The apparent displacement of an object with reference to another object when seen from two different points.

Parallel

Two surfaces or lines that all parts thereof are equidistant from each other (can never cross each other).

Parallel circuit

A circuit containing two or more parallel paths for electrons supplied by a common source.

Parallel jaw pliers

Pliers that have a toggle joint which permits the jaws to stay parallel to each other regardless of the extent of their opening.

Parallel rulers

A draftsman's tool consisting of two straight-edges or rulers connected in such a way that they remain parallel to each other regardless of the distance between them.

Parallelogram

A four-sided plane figure whose opposite sides are parallel and equal (square, rectangle, rhombus, and rhomboid).

Parallels

Blocks used in machining for alignment, usually in matched pairs.

Parameter

Any given constant or element whose values characterize one or more of the variables entering into a system of expressions, functions, etc.

Parametric curve

A curve represented by equations for all coordinates in terms of an independent variable. As the independent variable changes, all the coordinates change and the point moves along the curve. Example: y =a sin t and y = a cos t.

Part number

A number which serves to uniquely identify a component or assembly; in many instances, products and raw materials are also assigned numbers.

Parted core box

A core box made up of two or more parts for making patterns in a foundry.

Parted pattern

A pattern made of two or more parts.

Parting sand

A compound which is used on the sand in the drag to prevent sand in the cope from sticking to it. Burned molding sand is also used for this purpose.

Parting tool

In machine shop work this is a lathe cutting tool designed to plunge straight into the work to cut it completely in two. Also called a cutoff tool.

Parts program

A specific and complete set of data and instructions written in one of the source languages for the purpose of manufacturing a part on an nc machine. Sometimes called manuscript.

Parts programming, computer

The preparation of a manuscript in computer language and format required to accomplish a given task. The necessary calculations are to be performed by the computer.

Parts programming, manual

The preparation of a manuscript in machine control language and format required to accomplish a given task. The necessary calculations are performed manually.

Pascal

Unit for measuring pressure

Password

A unique string of characters that a program, computer operator, or user must supply to meet security requirements before gaining access to data.

Pasted core

A core made in two parts and pasted together.

Patch bolt

A bolt used for making repairs in boiler plate, etc. It is threaded the full length of the body, and is driven into the work with a square shank which extends from the flat head, and which may be removed after the bolt is in position.

Path storage

Storage media containing interpolated path of tool and instructions for auxiliary functions.

Pattern

Anything shaped or designed to serve as a model or guide in making something else.

Pattern shop

The shop or department where wooden patterns are made which are used in the production of castings.

Pawl

A hinged or pivoted member shaped to engage with ratchet teeth, either to drive a ratchet wheel or stop its reverse motion.

Pearlite

Form of steel which has alternating layers of ferrite and cementite.

Pedestal grinder

A grinding wheel or wheels mounted on a central column.

Peel test

Destructive test which mechanically seperates a resistance welded lap joint.

Peen

To stretch or shape metal by hammering with the peen of a hammer; that is, with the end opposite the face of the hammerhead.

Peen ramming

Ramming done with the peen end of the ramming tool.

Penetrating oil

A thin, special oil designed to penetrate rust, corrosion, etc., To loosen parts that are stuck together.

Penetration

The act or power of penetrating physically; the act of entering or piercing (measuring the amount of penetration is a part of testing the hardness of metals with certain specialized equipment).

Pentacle

A figure composed of five straight lines, making a star that includes a pentagon.

Pentagon

A figure with five angles and five sides.

Percussive welding

A welding technique or process in which a hammer blow (or something similar) occurs simultaneously with an intense discharge of electrical energy.

Perforating

Usually a stamping operation performed with the aid of a die and produces a group of punched or slotted holes.

Perimeter

The bounding line of any figure of two dimensions. The sum of the sides of a plane figure.

Peripheral speed

The speed of the circumference of a round part (as a shaft or wheel). It is usually expressed in feet per minute. The number of feet of circumference which passes a given point in one minute.

Periphery

The outside circumference of cylindrical objects; a line bounding the surface of any body.

Permanent magnet

Hardened steel or special alloy which retains the magnetic effect a magnetizing force has been removed.

Permanent mold

A mold used for repetitive work; for repeated production of similar castings. Usually made of metal.

Perpendicular

Being at right angles to the plane of the horizon; upright or vertical. Math: meeting a given line or plane at right angles.

Perspective

The art of representing, by a drawing made on a flat or curved surface, solid objects or surfaces conceived of as not lying in that surface; delineation of objects as they appear to the eye. The art of conveying the impression of depth and

Persuader

A shop term given any kind of lever, bar, etc., Which might be used to exert greater pressure in some manual task; i.e., a pipe slipped over the handle of a chuck wrench to tighten or loosen the chuck more than could be done with the chuck

Pewter

An alloy of tin, lead, and antimony; formerly a common metal for making tableware.

Phantom drawing

A drawing added to the regular drawing to show the part in another position, or the method of connection, or its relation to the whole, etc. This is accomplished with the use of phantom lines, which are very thin, interrupted lines.

Phillips machine screw

A wood or metal screw of varying size, with two slots at right angles in the head, with the center deeper than the ends. They require a special screwdriver to insert or remove the screws. The automotive industry uses them extensively, espe

Photomicrograph

A picture taken with a combination camera and microscope for the study of metallic sections. Magnification may range as high as 500 times actual size.

Physical properties

Properties or qualities other than mechanical that pertain to the physics of a material.

Physical testing

Examination of a material to determine its physical propoerties.

Pi

The sixteenth letter of the greek alphabet, commonly used to designate the ratio of the circumference of a circle to its diameter (pi x diameter equals circumference). Its value is 3.14159 plus.

Piano wire

A very strong wire with a tensile strength of over 300,000 pounds per square inch.

Pickle (chemical treatment of steel)

A bath of diluted sulphuric or nitric acid, used to clean castings and aid in their seasoning.

Picofarad

The same as a micromicrofarad.

Pig

An ingot of cast iron. Originally, iron workers thought that these ingots as they were poured from the furnace bore a resemblance to the animal, hence the name.

Pillar file

A narrow file used for cutting grooves, etc.

Pillow block

A two-pieced bearing used to support a shaft.

Pilot

A cylindrical portion, either integral or removable, at the entering end of a counterbore to maintain alignment with the hole being counterbored.

Pilot drill

A small drill used to start a hole in order that the larger finish size drill will run true.

Pin

A piece of metal, generally cylindrical, possibly tapered, used for fastening separate articles together. A pin may also be used as a support by which an article may be suspended from another.

Pin punch

A small slender punch designed to drive an object out of a hole. They are flat on the end, and made in a variety of sizes.

Pin spanner

A type of wrench designed for nuts which have holes in their periphery to receive the spanner pin. These nuts do not have flats on the periphery like standard nuts.

Pin vise

A small vise with a v cut in each jaw opposite each other, used for gripping round objects.

Pin wrench

Used on round nuts with two holes in the face to receive the pins of the wrench.

Pinch bar

Another name for a crowbar.

Pinchers

A tool basically similar to pliers, but the jaws are curved inward toward each other.

Pinion

The smaller of two mating gears.

Pinning

Chips clogging a file.

Pipe coupling

A short piece of threaded pipe used to connect two pipes together.

Pipe cutter

A portable tool for cutting pipe.

Pipe die

A portable tool for cutting screw threads on a pipe.

Pipe fittings

A general term refering to the variety of pipe connectors used in plumbing.

Pipe hangar

Any of a variety of devices for suspending pipe from walls, ceilings, etc.

Pipe thread

A v-type thread used on pipe and tubing, having a taper of ¾ inch per foot. The taper permits leak-proof connections.

Pipe vise

A vise designed to hold pipe firmly while work is being done on it. Large pipe vises have a chain used for clamping, smaller pipe vises have v-shaped jaws for clamping the pipe.

Pitch

The distance from a point on one screw thread to the corresponding point on the next thread, measured parallel to the length axis of the threaded part.

Pitch diameter

In a gear, the diameter of the pitch circle of the gear wheel. On a thread, it is the major diameter of the thread minus the depth of one thread.

Plane

To make smooth, or machine with a planer. Any flat or uncurved surface.

Plane angle

An angle made by lines lying in one plane.

Plane trigonometry

The same as trigonometry.

Planer (machine tool)

A machine used to machine flat surfaces of large size to a smooth finish, having a stationary tool and bed, and a reciprocating table to which the work is fastened.

Planetary (gearing)

Pertaining to or denoting a type of gearing in which one or more small wheels mesh with the toothed circumference of a larger wheel, around which they revolve.

Planish

To toughen and polish a metal surface by light hammering.

Planometer

A surface plate.

Plant manager

A person whose primary duty is usually the construction of plant equipment; he is often a mechanical engineer by training.

Plasma

Temporary physical condition of  a gas after exposure and reaction to an extremely high temperature.

Plasma arc cutting

Process of metal cutting using an electric arc and fast flowing ionized gases.

Plasma flame

See flame spraying.

Plasma spraying

Thermal spraying process which uses a non-transferred plasma arc to melt and propel the coating material to the base metal.

Plaster mold casting

Used primarily for aluminum, plaster molds give a better surface finish to the castings than do sand molds.

Plastic welding

Process in which heated air softens and fuses synthetic plastic materials.

Plasticity

Ability of a metal to bend without breaking.

Platen

In a machine tool, the adjustable table that carries the work. A flat working surface for laying out or assembling metal work.

Plenum

Pressure equalizing chamber.

Pliers

Small pinchers for bending, holding, or cutting.

Plotter

A device which will draw a facsimile of coded data input such as the cutter path of an nc program.

Plug gage

An accurate metal plug used to gage the size of holes in machine work.

Plug tap

See tap.

Plug weld

A method of fastening plates together by welding through a hole in one or both plates.

Plugboard

A perforated board that accepts manually inserted plugs to control the operation of equipment.

Pneumatic

Operated by or pertaining to air pressure.

Point-to-point

An nc machine type which provides control only of discrete positions at which a machine operation is performed. The path and rate of movement between points are not under continuous control.

Point-to-point control system

A system in which controlled motion is required only to reach a given end point with no path control during the transition from one end to the next. The most common application is in numerically controlled drill presses.

Polar coordinates

Also called spherical coordinates because they define the points on the surface of a sphere. Polar coordinates are defined in terms of two angles and a radius arm. The length of the radius arm defines the radius of a circle while the angul

Polarity

Having a definite positive or negative sign.

Polarity

The quality of having opposite poles. The quality of being attracted to one pole and repelled from the other.

Polarized circuit

The use of a white or marked wire for the ground side of a circuit.

Pole

One end of a magnet, either north or south.

Polish

To make smooth or glossy by friction.

Polling

A technique by which each of the terminals sharing a communications line is periodically interrogated to determine whether it requires servicing. The control station sends a poll which, in effect, asks the terminal selected, if it has anything to send.

Polygon

A figure having many sides and angles.

Poppet

A term seldon used meaning the headstock of a lathe or a lathe center.

Porosity

Gas pockets or voids in a metal.

Portable crane

A frame mounted on wheels which carries a hoisting device. Useful where overhead cranes are not available to handle weights too heavy for a man to lift.

Portable storage

A storage medium that can be easily transported without loss of stored data.

Position accuracy

The ability of a mechanical device or system to position a command location from a randomly arrived point of origin with a defined tolerance regardless of the direction of approach to this command location.

Position readout

A visual display of the absolute position of a machine axis.

Position sensor or position transducer

A device for measuring a position, and converting this measurement into a form convenient for transmission.

Position storage

Storage media containing major positions of tool and instructions for auxiliary functions.

Positioning control system

A system in which the controlled motion is required only to reach a given end point, with no path control during the transition from one end point to the next.

Positioning time

The time required to move from one location to another location and be ready to perform an operation at this second or new location.

Positive feed

On machine tools, that type of motion transmitted by gears, rather than belts or clutches.

Post drill

A drilling machine designed to attach to a column or post.

Post processor

A computer program that takes a generalized or centerline output and adapts it to the particular machine control unit/machine tool combination that will machine the part.

Postheating

Temperature to which a metal is heated after after an operation has been performed.

Pounce

In drafting, the term is applied to a fine powder used to facilitate inking when applied to the surface of a tracing linen.

Powder metallurgy

The science and technique of manufacturing objects from finely powdered metals and alloys, shaped under controlled pressures and temperatures.

Power feed

The automatic feed of machine tools.

Power hammer

A hammer used for heavy work, operated by hydraulics, air, or mechanical means.

Power loss

Loss in a circuit due to resistance of conductors.

Precision

The quality of being sharply or clearly determined; strictly accurate; exact. Closeness of agreement among repeated measurements of the same characteristic by the same method under the same conditions.

Preheating

Temperature to which a metal is heated prior to performing an operation.

Preparatory function

A command changing the mode of operation of the control such as from positioning to contouring or calling for a fixed cycle of the machine.

Preset tool

Cutting tool placed in a holder so that a predetermined geometrical relationship will exist with a gage point.

Press fit

The same as force fit.

Pressure welding

A number of welding methods in which the weld is obtained by pressure.

Pressure, atmospheric

The pressure due to the weight of the atmoshere

Pressure, static

The potential pressure exerted in all directions of a fluid at rest.

Pressure, total

The sum of the velocity pressure and the static pressure

Pressure, vapor

The pressure exerted by a vapor.

Pressure, velocity

The kinetic pressure in the direction of flow necessary to cause a fluid at rest to travel at a certain velosity.

Prickpunch

A small center punch, usually used for layout work. The point is usually made at a 60 included angle, while the center punch point angle is 90 .

Prime factor

A factor which is a prime number is called a prime factor. Thus, 2 and 3 are factors of 6; 3 is a prime number, and would also be a prime factor.

Prime number

A prime number is one which has no factors except itself and 1. Thus, 3, 5, 7, etc., Are prime numbers.

Printer

A device, usually mechanical that prints results or output of a computer; ranges from a single stick or flying typebar printer (as on a typewriter) to a high-speed unit that prints characters on a line at speeds up to 5000 lines per minute.

Procedure qualification record pqr

Document containing the actual welding variables used ot produce an acceptable test weld in order to qualify a welding procedure specification.

Process annealing

A heat treating operation in which iron base alloys are heated to near the lower limit of the critical temperature and then cooled.

Process control

Pertaining to systems whose purpose is to provide automation of continuous operations. This is contrasted with numerical control, which provides automation of discrete operations.

Processor

That portion of a computer which controls the operation input and output devices and operates on the received, stored, and transmitted data. Its circuitry includes the functions of memory, logic, arithmetic and control.

Production capacity

The highest, sustainable output rate which can be achieved with the current product specifications, product mix, worker effort, plant and equipment.

Profile

To machine an outline by moving a small rotating cutter, usually controlled by a master cam or die.

Profiling machine

A type of milling machine whose cutter can be made to follow a pattern or profile.

Profilometer

An instrument for measuring surface roughness. The diamond tracer point moves slowly across the surface and indicates the average deviation by a meter in microinches. It may be applied to flat, cylindrical, or curved surface.

Program

A set of instructions that defines a desired sequence of conditions for a process or function, and the operations required among those conditions.

Program stop

A miscellaneous function command to stop the spindle, coolant and feed after completion of other commands in the block. It is necessary for the operator to push a button in order to continue with the remainder of the program.

Programmer

A person who prepares the planned sequence of events for the operation of a numerically controlled machine tool. The programmer's principal tool is the manuscript on which the instructions are recorded.

Programming

The ordered listing of a sequence of events designed to accomplish a given task.

Programming, computer

The preparation of a manuscript in computer language and format required to accomplish a given task. The necessary calculations are to be performed by the computer.

Programming, manual

The preparation of a manuscript in machine control language and format required to accomplish a given task. The necessary calculations are to be performed manually.

Projection (blueprint)

A method by which a view or views may be used as an aid to secure additional views.

Projection welding

A resistance welding process in which the localization of heat between surfaces is obtained by the use of projection.

Prom

Programmable read only memory. A memory that can be programmed only by special routines. Once programmed with permanent data, such as a math formula, it becomes a rom or read-only memory.

Proposition

A statement of a truth to be demonstrated (a theorem) or of an operation to be performed (a problem).

Proton

A positively charged particle.

Protractor

An instrument for measuring or laying off angles.

Psychrometer

A device having both a dry and wet bulb thermometer. It is  used to determine the relative humidity.

Puddle

Portion of weld that is molten due to the heat of welding.

Pull broach

A broach which is pulled through the work rather than pushed. Pushing is the most common method.

Pulley

A wheel grooved to receive a rope, and usually mounted in a block. Used to increase the mechanical advantage of an applied force and to transmit or change the direction of power by means of a flexible belt or rope.

Pulley lathe

A lathe used for turning the face, either crowned or straight, on a pulley.

Pulley tap

A screw-cutting tap with an unusually long shank. When cutting a thread on the periphery of a hub, the long shank permits the end of the tap to extend beyond the face of the pulley, allowing free movement of the tap wrench.

Pulsation welding

A welding process in which the current is interrupted without changing the location of electrodes or release of pressure.

Pulse

A pattern of variation of a quantity, such as voltage or current, consisting of an abrupt change from one level to another, followed by an abrupt change to the original level.

Pulse arc welding

Welding arc in which the current is interrupted or pulsed as the welding arc progresses.

Punch

A tool usually made of steel, having a shaped end for making holes, forming identations, etc. Also the male member of a die set.

Punch press

A machine designed to form metals or punch holes in metals by means of a punch moved by a ram, against a die which is firmly attached to the bed of the machine.

Push broach

A broach which is pushed through the work rather than pulled.

Pyramid

A figure having several triangles with a common vertex for sides, and a plane polygon for its base.

Pyrometer

An instrument for measuring high degrees of heat, as caused by electrical resistance, degree of incandescence, expansion, radiation, etc.

Pythagorean

Relating to pythagoras, greek philosopher of the sixth century b.c.

Pythagorean theorem

The theorem that the sum of the squares of the legs of a right triangle is equal to the square of the hypotenuse.

Quadrant

In math, the quarter of a circle or its circumference.

Quadrilateral

A figure bounded by four straight lines terminated at four angles.

Quadruple thread

A thread, usually of the square or acme type, which has four helixes making the lead four times the pitch.

Quality control (qc)

The function of establishing and maintaining specified quality levels for products.

Quantum

The numerical value of the smallest unit of measure used in a system.

Quarter bend

A bend of 90 .

Quarter turn belt

An arrangement of belting which drives two shafts at right angles to each other.

Quench

To cool a metal rapidly from a high temperature by contact with liquids, gasses, or solids.

Quench aging

Change in metal produced by rapid cooling after heat treating.

Quench annealing

Process used to soften austenitic ferrous alloys by solution heat treatment.

Quench hardening

Hardening an iron alloy by austenitizing followed by rapid cooling so some of the austenite becomes martensite.

Quenching oils

Oils used in heat treating. Fish oils are suitable, but have offensive odors. Different oils are often compounded and sold under trade names (vegetable, animal, mineral, and fish).

Quick change

An arrangement of gears on a lathe to permit the change of automatic feed by means of levers, without actually removing and replacing gears.

Quick return

The mechanism on certain machine tools that may be engaged so that the work table will return to its starting point on the noncutting cycle.

Quill

A steel tube on the head of some machine tools (particularly vertical milling machines and drill presses) which contains bearings and the rotating spindle of the machine. It has a vertical movement only and may be locked in position.

Rack

A flat strip with teeth designed to engage the teeth of a gear in order to change rotary motion to reciprocating motion.

Radial drill (drilling machine)

A heavy drilling machine with the drill spindle mounted on a beam which is capable of revolving in a 360 circle, also with vertical adjustment. The controls and spindle are also movable in a horizontal plane, permitting great versatility of movement.

Radiation

The transfer of heat without an interviewing medium

Radiation, thermal

The transmission of energy by means of electromagnetic waves.

Radical

Pertaining to the root or roots of a number.

Radiograph

Photograph made by passing x rays or gamma rays through an object and recording variations in density.

Radiographer

One who performs radiographic operations.

Radiographer's exposure device

Instrument containing the x-ray source for making radiographic records on sensitized film.

Radiographic interpretation

Reading of the films to determine cause and significance of discontinues below the surface of the material.

Radiographic screens

Sheets, either matallic or fluorescent, used to intensify the radiation effect on film.

Radiography

Use of radiant energy found in x rays or gamma rays to examine opaque objects.

Radius

A straight line from the center of a circle or sphere to its periphery. A circular area or boundary measured by the length of its radius.

Radius gage

A tool used to check the size of radii and fillets.

Radius planer

A special planer for planing links for locomotives, arcs, etc.

Rake

The amount of set in a cutting tool.

Rake angle

On a lathe cutting tool the rake angle is the angle between the top face of the tool and a plane parallel to the top of the shank, with the cutting edge of the tool as its vertex. On a milling cutter the rake is the angle between the face

Ram

The part of a machine tool that carries a tool head in a reciprocating motion; i.e., a shaper ram.

Rammer

A tool used to ram or pack the sand around a pattern in foundry work.

Random access

The process of obtaining data from, or replacing data into, storage where the time required for such access is independent of the location of the data most recently obtained or placed in storage.

Random numbers

A series of numbers believed to be free from conditions which might bias the result of a calculation.

Range

The set of values that a quantity or function may assume.

Rank

To arrange in an ascending or descending series according to importance.

Rapeseed oil

An oil used in the heat treatment of steel, and as a lubricant. It is obtained from the seed of rape, an old world annual grown as a forage crop for sheep and hogs.

Rapid traverse

A mechanism which can be engaged to bring the work table of a milling machine rapidly into cutting position, or the table returned quickly to the starting position for the next cut.

Rapping bar

An iron or steel bar used to lift a pattern from the mold in foundry work.

Rasp

A tool like a very coarse file, having coarse pyramidal projections for abrasion.

Rat tail file

A round, tapered file.

Ratchet

A mechanism consisting of a notched wheel, the teeth of which engage with a pawl, permitting motion of the wheel in one direction only. Ratchets are much used to rotate hand tools such as screwdrivers, drills, and wrenches.

Rate of speed

In machine work, rate of speed is usually expresses in revolutions per minute, or in peripheral feet per minute.

Raw

A path perpendicular to the edge of a tape along which information may be stored by presence or absence of holes or magnetized areas.

Raw data

Data which has not been processed or reduced.

Raw material

Material in or nearly in its natural or original state; unprocessed material.

Raw storage

Storage media, such as drawings, containing all information, (geometry of part, cutter size, feeds and speeds, etc.) Necessary for preparation of the manuscript.

Rawhide gears

Silent operating gears made of compressed disks of rawhide.

Rawhide hammer

One of a number of different types of soft hammers which will not damage metal parts, the head is made of rawhide. Other materials used for this type of hammer include plastic, babbitt, lead, and brass.

Rays

See infrared rays and ultraviolet rays.

Reactance

Opposition to the flow of alternating current as a result of inductance or capacitance.

Reactive load

A load consisting of inductive reactance which causes the current to lag the applied voltage.

Read

To gain information, usually from some form of storage. To sense the characters involved in numerical input information.

Readout

A visual display of the cutting tool coordinate axes locations in relation to the extablished zero.

Readout, command

Display of absolute position as derived from position command. Note: in many systems the readout information may be taken directly from the dimension command storage. In others it may result from the summation of command departures.

Readout, position

Display of absolute position as derived from position feedback transducer.

Ream

To finish a drilled or punched hole to an accurate dimension and finish with a rotating fluted tool of the required diameter.

Reamer

A fluted cutting tool designed to remove a small amount of metal from a hole and provide a fine finish.

Recarburize

Adding carbon to molten cast iron or steel.

Reciprocating

To move backward and forward as the table on a planer or the ram and tool assembly on a shaper.

Rectangle

A right angled parallelogram; a plane figure with opposite sides equal in length and containing four right angles.

Rectangular

Having one or more right angles. Resembling a rectangle in shape or appearance.

Rectangular coordinates

A system of two or three mutually perpendicular axes along which any point can be located in terms of distance and direction from any other point.

Rectified alternating current

Alternating current made to flow in one direction.

Rectifier

Device such as a diode or a circuit which acts like one way valve .

Red lead

A lead prepration having a fine red color, used chiefly as a pigment; in machine shop work it is also used as a lubricant for dead centers. White lead is also used for this purpose.

Reducing flame

Oxyfuel gas flame with a slight excess of fuel gas.

Reduction gears

Gears used to reduce the speed between driving and driven gears.

Reduction of area

Difference in cross sectional area of a speciman after fracture as compared to original cross sectional area.

Reed taper

One of a variety of standard tapers used in machine tool spindles. The reed taper is a short adaptation of the jarno taper.

Reference dimension

A reference dimension is a dimension without tolerance used for information purposes only.

Reference gages

Gages used to test the accuracy of inspection gages.

Reference point

A point defined within the limits of travel to locate the spindle in relation to the part.

Reflex angle

An angle greater than a straight angle.

Refractory

Material resistant to heat or difficult to melt.

Refrigerant

A substance which produces a refrigerating effect while vaporizing or expanding.

Refrigeration

The transfer of heat from a place where it is undesireable to another place.

Regeneration

The restoration of stored information.

Register

An air grille with a built-in damper or shutter.

Regular polygon

A polygon whose sides are the same length and whose angles are equal.

Regulator

The arrangement of gages and valves which control the flow of acetylene and oxygen used in oxyacetylene welding.

Reinforcement of weld

Excess metal on the face of a weld.

Relative humidity

The percentage of water vapor present in a a quantity of air comapred to the amount it can hold at that temperature.

Relay

A magnetic switch. The magnet operates switch contacts by activating a coil.

Reliability

The probability that a device will function without failure over a specified time period or amount of usage.

Relief

A slight variance in the dimension of a machine part to allow for clearance. In drawing, something is said to be in relief when it stands out prominently from a surface.

Relief angle

The angle between the front of a cutting tool and the face of the material upon which it operates. Necessary to prevent rubbing and friction which would heat and dull the tool.

Relieving

The removal of material behind the cutting edge of a tool to reduce rubbing and friction.

Reluctance

The resistance to the flow of magnetic lines of force.

Repeatability

Closeness of agreement of repeated position movements to the same indicated location and under the same conditions.

Replicability

The capability of a product to be reproduced over and over with the same fidelity of purpose and simplicity of installation.

Report generator

A computer program used to produce reports from existing sets of data.

Reproducibility

The ability of a system or element to maintain its output/input precision over a relatively long period of time.

Residual stress

Stress still present in a body freed of external forces or thermal gradients.

Resistal

A high quality stainless steel. It resists rust and acid, and is nonmagnetic.

Resistance

The act or power of springing back to a former position or shape; elasticity.

Resistance seam welding

Resistance welding process which usually uses round, rotating electrodes to make a continuous seam or overlaping spot welded seam.

Resistance welding

A pressure welding process in which the heat is obtained from the resistance to the flow of an electrical current.

Resistor

A component designed to resistance a specific value of flow of electric current.

Resolution

The smallest increment of distance that a machine control unit can act upon. It may range anywhere from one tenth to a thousandth of an inch in most systems.

Resolver

Often called synchro. An electrical device used to feed back a signal to the machine control unit error detector. The resolver is usually on the end of a lead screw of a numerically controlled machine tool.

Response time

The time span between the end of a request for information or action and beginning of receipt for the information or action.

Retrofit

The application of numerical controls to machines which were not originally designed as part of such a system.

Return bend

A pipe fitting or a pipe bend shaped like the letter u.

Reversing gear

The gear which reverses a machine or engine.

Revolution counter

More often called a tachometer.

Revolutions per minute

In machine shop work, usually refers to the number of times a spindle revolves in one minute; abbreviation, rpm.

Rhomboid

A parallelogram whose opposite sides and opposite angles are equal, but has not right angle.

Rhombus

An equilaterial parallelogram having the angles usually, but not necessarily, oblique.

Riddle

A sieve used in foundry work for sifting sand, etc.

Riffler

A small, curved rasp or file, usually used for enlarging holes or filing inside surfaces.

Rigger

A worker who moves, installs or removes, heavy equipment. One who, with the aid of a tackle and heavy tools, works with heavy equipment.

Right angle

An angle whose sides are perpendicular to each other; an angle of 90 .

Right-hand screw

A screw which advances when turned to the right (clockwise).

Right-hand tools

In reference to cutters for machine tools are those which cut from the right to the left; in reference to hand tools are thos designed to be used with the right hand.

Ring

A plane figure included between two circumferences with the same center.

Ring bolt

A bolt with a ring where the head is normally located; an eye-bolt. Usually used for insertion of a hook into the ring for lifting purposes.

Ring gage

A ring-shaped gage used to check outside diameters.

Ring oiler

A bearing with a loose-fitting ring in the journal, the lower half of which is immersed in oil. As the shaft rotates, the ring also rotates to a lesser degree carrying oil to the bearing.

Ring thread gage

A ring-shaped gage with precision-made internal threads used to check (gage) outside screw threads.

Riser

A reservoir of molten metal used to compensate for the contraction of cast metals as they solidify. Also, an air passage in a mold.

Risers

Wires or cables which run vertically.

Rivet

A metal pin with a head, used for fastening two pieces together by shaping the end opposite the head after the two pieces have been joined by the rivet.

Rivet forge

A portable forge used to heat rivets on location. Used by construction workers, boiler makers, and iron workers to heat rivets.

Rivet set

A steel punch with a cupped face used to set rivets.

Riveting

The clinching of rivets; large rivets are headed (clinched) after heating, small rivets when cold.

Rockwell

The rockwell hardness tester is essentially a machine that measures hardness by determining the depth of penetration of a penetrator into the specimen under certain fixed conditions of test. The penetrator may be either a steel ball or a diamond point.

Rolled threads

A thread produced by a blank being forced through hardened rolls under heavy pressure. It is a production method requiring expensive machinery, but capable of producing large quantities at low cost.

Roller bearing

A bearing employing steel rollers to lessen friction between the parts of a mechanism.

Roller ramming machine

A foundry molding machine adapted to long thin work.

Rolling

The process of shaping metal by passing it through a series of driven rolls.

Root

The surface of a screw thread which lies between adjacent threads.

Root crack

Crack in either the weld or the heat affected zone at the root of a weld.

Root diameter

Same as minor diameter.

Root of joint

Point at which matals to be joined by a weld are closest together.

Root of weld

That part of a weld farthest from source of weld heat or the filler metal side.

Root penetration

Depth to which weld matal extends into the root od a welded joint.

Rose countersink

A fluted countersink made in a cone shape.

Rose cutter or rose mill

A hemispherical profiling cutter used in die work, and for making seats for ball joints, etc.

Rose reamer

A reamer usually used for heavy work. It is designed to cut on its end, which is beveled, instead of on its sides.

Rosette weld

See plug weld.

Rotary

That which turns upon its axis, like a wheel.

Rotary cutter

A multiple-tooth cutter which rotates upon a shaft (arbor), most commonly used on milling machines.

Rotary table

An attachment for milling machines, upon which work may be mounted by various methods and revolved any required number of degrees.

Rotate

To revolve; to turn upon an axis.

Rotating

The act of revolving around an axis.

Rotor

The revolving part of a rotating electrical machine.

Roughing

The rapid removal of stock in machining operations without regard for surface finish.

Roughing tool

A tool-bit designed for roughing work.

Round-point chisel

A chisel designed to cut grooves.

Router

See hand miller.

Routine

An ordered set of instructions that may have some general or frequent use.

Routing sheet

A list of the sequence of moves between operations or work centers.

Rubylith

A laminated material with a mylar sheet base, and an easily cut, red plastic optically opaque sheet lightly adhered. Used in the cut-and-peel process of producing artwork.

Rule

A tool used for actual measurement and calibrated in various ways; in fractions of an inch or millimeters. Rules are made with a straight edge which may be used as a guide for scribing lines.

Rumble or tumbler

A revolving cylinder used to clean sand from castings in a foundry.

Runner

The channel through which molten metal flows to the casting and risers from the sprue. In plastics, the groove in an injection mold through which the plastic composition flows from the sprue to the gate.

Running fit

Refers to the mating of parts to permit motion between them with negligible friction.

S-wrench

A wrench whose handle is s-shaped. It may have openings on one or both ends, either fixed or adjustable.

S.A.E. steels

Steels identified by a numerical system devised by the sae. (1) indicates a carbon steel, (2) nickel steel, etc. The first number indicates the class to which the steel belongs, the second represents  percentage of alloying elemement .

S.A.E. threads

Known as the national fine series, these threads have a finer pitch than the u.s. standard series, but are of the same form.

Saddle

The base of the slide rest that lies on a lathe bed and carries the cross-feed and compound assemblies; the crossbar of a boring mill or planer which carries the toolhead; also the movable plates which carry the drill spindle and feeding mechanism.

Safe edge

The edge of a file which has no teeth, making it possible to file one surface at a corner without filing the surface which is at right angles to the one being worked.

Safety factor

The ultimate strength of the material divided by the allowable working load; the element of safety needed to make certain that there will be no structural failures due to overloading, unusual loads, variation in materials and workmanship,

Sal ammoniac

Ammonium chloride (nh cl). Used as a flux for soldering, and in other nonmetalworking industries.

Sampled data

Data in which the information content can be, or is, ascertained only at discrete intervals of time. Note: sampled data can be analog or digital.

Sand hole

A cavity formed in a casting (not intentionally) by facing washed into the mold during pouring, and by loose sand. Sand holes are sometimes a problem to the machinist during machining operations.

Sand mold casting

A casting process in which molten metal is poured into a cavity that has been formed in a sand mold.

Sandblast

To clean metal by means of sand driven at high speed by compressed air through a nozzle.

Sandblasting

The use of sand and air pressure to act as an abrasive cleaner for metal, stone, brick, etc. It is used in many shops to remove scale, dirt, etc., From metal castings prior to machining operations.

Saturated vapor

Vapor in contact with a liquid.

Scab

A small wart-like projection on the surface of a casting, caused by too much slicking, and forming when small patches of the mold face wash off.

Scale

A metal, wood or glass tool bearing accurately spaced lines or graduations for use in representative (not actual measurement. In draftiing, the size of a drawing in relation to the the object represented.

Scale

The coating of oxide that forms on heated iron, etc., Also an incrustation as on the inside of boilers.

Scale measurement

Representative measuring, not actual; i.e., a scale with graduations indicating it is 12 inches long might actually by 12 1/8 inches long. They are used to compensate for expansion and contraction of metals during heat treatment.

Scaled drawing

A drawing made smaller or larger than the object represented, but proportionate in all respects with the proportions specified on the drawing itself.

Scalene triangle

A triangle in which no two sides are equal.

Scan

To examine sequentially part by part.

Scarfing

In forging, the tapering of two ends to be joined to prevent a thick joint.

Schackle bolt

A bolt used to pass through the open end of a shackle and the part connected to it.

Schedule

A listing of jobs to be processed through a work center, department, or plant and their respective start dates as well as other related information.

Scheduling

The process of setting operation start dates for jobs to allow them to be completed by their due dates.

Schematic

A line drawing of an electric circuit showing components and connections in the form of symbols.

Sclerometer

An instrument for testing the hardness of metal. A diamond is drawn over the surface, then back, and the resulting scratches are compared to a standard scratch.

Scleroscope

Measures the hardness of the work in terms of elasticity. A diamond-tipped hammer is allowed to drop from a known height on the metal to be tested. As this hammer strikes the metal, it rebounds, and the harder the metal, the greater the rebound.

Scrap

In foundry work, pig iron that has been melted in the cupola and is to be remelted.

Scrap iron

A general term referring to all kinds of salvaged iron and steel that is to be used in the making of new steel.

Scraping

The process of removing metal by the use of scrapers. The scraping is done by hand, is extremely slow, but results in a smoother and more accurate finish that can be done by filing.

Scratch hardness

Hardness of a metal determined by measuring the width of a scratch made by a cutting point under a known pressure.

Scratch pad memory

A high-speed memory used to temporarily store a small amount of data so that the data can be retrieved quickly when needed.

Screw

Usually thought of as a thread, the screw is a helix wound around a cylinder to certain specifications. The most common is a single helix; however, there are also double and multiple types.

Screw adjusting caliper

A machinist tool similar to the firm joint caliper, but in addition it has a spring and screw control permitting delicate adjustments.

Screw jack

A jack (lifting tool) actuated by a square threaded screw.

Screw pitch gage

A gage used to determine the number of threads per inch on a bolt, screw, nut, etc. It usually consists of a number of metal leaves with the edge of each leaf cut with a thread of indicated size. In determining the number of threads per inch

Screw-cutting lathe

A lathe with the gearing and leadscrew which will permit the cutting (chasing) of threads. Most engine lathes are now screw cutting lathes. Automatic bar machines are often referred to as screw machines or automatic screw machines.

Screw-slot cutter

A milling cutter used to cut the slots on the heads of screws.

Screwdriver

A hand tool with a handle on one end and a steel bar flattened on the other end to fit the slots of screws. They are made in various sizes, and the competent workman attempts to use the size appropriate to the job to be done.

Screwstock

A shop term used to refer to softer steels used on screw machines.

Scribe

To draw a line with a scriber or other sharp-pointed hand tool.

Scriber

A pointed, hardened steel instrument for making fine lines in layout work.

Scroll

The spiral-like thread on the face of a lathe chuck which engages the chuck jaws.

Scroll saw

A narrow bladed saw or sawing machine bearing such a blade, for doing curved or irregular work.

Scroll shears

A sheet-metal, gapshearing machine designed to cut irregular shapes. Usually hand operated.

Sea-coal

A foundry term referring to finely ground, soft coal.

Seam

A sheet-metal joint in which the edge of one piece is turned or folded over the edge of another.

Seam welding

Tangent or overlapping spot welds made by a resistance-welding process.

Seaming iron

A tool used by sheet metal workers to set seams.

Seamless tubing

Drawn tubing without joints.

Search

To examine a set of items for one or more having a desired property.

Secant

Geometry: a straight line intersecting a given curve. Trigonometry: a line drawn from the center of a circle through one extremity of an arc to the tangent drawn from the other extremity of the same arc.

Second class lever

A lever where the weight is applied between the power and the fulcrum, as in the case of a wheelbarrow.

Second cut file

A file on which the spacing of the teeth is closer than on a bastard, and farther apart than on a smooth. Medium, it may be either single or double cut.

Secondary

The outgoing side of a transformer where the output voltage is available.

Secondary hardening

Tempering of some alloy steels at a higher temperature than normally used for hardening.

Section drawing

A drawing of a part as it would appear if cut through by an intersecting plane.

Sector

A part of a circle bounded by two radii and the arc subtended by them.

Segment

The portion of a path joining two successive points stored in a position storage medium.

Segment

A part of a figure cut off by a line or a plane; especially, the part of a circle included within a chord and its arc.

Segmental gear

An arc or portion of a gear, used to provide reverse motion to a shaft, etc.

Self-aligning bearing

A bearing supported in a manner which permits it to align itself to its shaft.

Self-centering

Equipment which automatically centers a piece of work.

Self-centering chuck

Same as universal chuck.

Self-centering punch

Same as bell center punch.

Self-hardening steel

An alloy tool steel which hardens when cooled in air.

Self-locking setscrews

A variety of  setscrews are available, among them one type with a deep slot in the head which may be spread to offer resistance to backing off, another is knurled on the point, the lefthand spiral of the knurl resisting the loosening effect of vibration.

Self-opening die

A die which opens automatically when the threading operation is finished, permitting the die to be removed quickly.

Self-tapping screw

A screw which cuts its own threads. Useful in soft metals and materials.

Sellers screw thread

A type similar to the national coarse or u.s. standard, with flats at the top and bottom of the screw equal to 1/8 of the pitch. It has the same 60 included angle.

Sellers taper

A standard taper of ¾ inch per foot, but not used as much as some of the others.

Semi-killed steel

Incompletely deoxidized steel which contains sufficiently disolved oxygen  to react with the carbon so the carbon monoxide is formed.'

Semiconductor

A conductor which has a resistance value between a condustor and an insulator.

Sensitive drilling machines

Small drill presses designed for small drills at high speeds. They were termed sensitive because they have no automatic feeds and being hand fed the operator is more sensitive to the drilling problems.

Sensor

A transducer or other device whose input is a quantitative measure of some external physical phenomenon and whose output can be read by a computer or by human beings.

Sequence check

A procedure to determine that a set of words or records is in memory.

Sequential

Arranged in some predetermined logical order.

Serial transmission

To move data in sequence, one character/bit at a time, as contrasted with parallel transmission.

Series circuit

A circuit which contains only one path for electrons to flow.

Series welding

A resistance welding operation in which a single welding transformer provides current for a number of welds being made simultaneously.

Servomechanism

An automatic feedback control system in which discrete motion is accomplished by the controlled variable or any of its time derivatives.

Setover

The distance a lathe tailstock has been set to the side of centerline of the machine. It is one method by which a taper may be cut on a workpiece.

Setscrew

An ordinary screw made with a variety of head designs, used to lock a movable part in one position. Setscrews are usually heat treated.

Setting down machine

A machine used in sheet metal work to close metal seams left by the burring machine.

Setup time

The time required to adjust a machine and attach the proper tooling to make a particular product.

Shackle

A device used to fasten parts together in such a way as to permit some motion between them. The common shackle is usually u-shaped steel with a bolt used to close the open end of the u when desirable.

Shaded-pole motor

A motor having each of its field poles split to accommodate a short-circuiting copper strap. The copper strap is wrapped around one of the split sections.

Shaft

A bar or axle used to impart motion through rotation. A shaft is usually made of steel, and usually cylindrical.

Shank

The part of a tool that is connected to the socket or handle; the unthreaded part of a woodscrew directly under and adjoining the head.

Shape

To finish a surface with a shaper tool.

Shaper

A machine tool having a reciprocating tool head; work is mounted on the shaper table which provides feed motion.

Shear (sheet metal)

To cut sheet or bar metal with shears or a similar instrument. A machine used for a shearing operation, more properly expressed in the plural (shears).

Shear fracture

Break in which crystalline material seperates as a result of the sliding under actio of shear stress.

Shear spinning

The process whereby a metal blank is clamped between the tail stock of the shear spinning machine and a power driven mandrel. The mandrel is the same size and shape as the finished part and the metal is forced to flow onto the mandrel by forming rollers.

Shear strength

Stress required to fracture a part in a cross sectional plane when two forces being applied are parallel and opposite, but slightly offset.

Sheave

A grooved wheel similar to a pulley, mounted in a block. Chain or rope runs in the groove to provide (usually) lifting action.

Shedder

A device used to eject blanks from a compound die.

Sheet

A flat, thin rolled steel member more than six inches wide and less than ¼ inch thick.

Sheet metal gage

A tool to determine the thickness of sheet metal.

Sheet tin

Thin sheet of steel or iron that has been coated with tin to prevent corrosion.

Shell drill

A type of drill used to enlarge already existing holes. It is mounted in an arbor when being used, and is hollow.

Shell reamer

A hollow reamer, which in use is mounted on an arbor.

Shell-end milling cutter

A cutter usually intended for heavy work, it is mounted on a tapered arbor, and may be removed from the arbor when the cutter has worn out or broken, and a new one installed.

Shielded metal arc cutting

Arc cutting process in which metal is cut by melting it with the heat of an arc between a covered electrode and the base metal.

Shielded metal arc welding

Arc welding process which melts and fuses the metals using the heat of an arc between a covered electrode and the base metal.

Shifter fork

Metal arms which straddle a belt and are used to shift the belt from a drive pulley to an idler pulley, or vice versa.

Shim

A thin piece of material used to fill in to level an object. To level up to a desired height, or true a surface with the use of shims.

Shoplifter

The term applied to a lifting device with a small table which is raised or lowered either by a motor or hand crane. It is equipped with casters so it may be pushed from place to place.

Short arc

Gas metal arc process which uses a low arc voltage.

Short circuit

A direct circuit across the electrical source providing no reistance to flow.

Short dimensions

Incremental dimensions when the number of digits is the same as normal dimensions except the first digit shall be zero, that is 0.xxxx for the under normal dimensions.

Short pouring

A situation when the molten metal in the ladle is not sufficient in quantity to fill the mold.

Shot peening

Working the surface of a metal by bombarding it with metal shot.

Shoulder

That part of a shaft where a sudden increase of diameter occurs.

Shoulder nipple

A short length of pipe threaded on both ends, but with an unthreaded portion in the middle.

Shoulder screw

A pivot pin for levers. It has a head on one end and a threaded portion on the other. Between these two parts is the shoulder which acts as the pin.

Show

A machine shop term used to designate a protective covering or plate used as a sliding surface for a moving part, as on a steadyrest.

Shrink fit

A fit obtained by heating the outer member of two mating parts until the heat expands it sufficiently to insert the inner member. As the outer piece cools it shrinks to form a very tight fit, designed to be a permanent and immovable mating of the parts.

Shrink rule

A rule laid out for representative measurement rather than actual measurement. It is used by pattern makers to allow for the shrinkage of the metal in which the pattern is to be cast.

Shrinkage

The failure of a casting to maintain its proper size and/or shape during cooling. The larger the casting, the greater is its propensity to shrink.

Shrinkage crack

A crack in a casting caused by the unequal cooling of its parts.

Shrouded gear

A gear with a flange attached to the back ends of the gear teeth to provide more strength or smoothness.

Side rake

The amount of transverse slope on the top face of single point cutting tools (shaper, planer, lathe, etc.), The cutting edge of the tool serving as the high edge of the slope (rake).

Side-milling cutter

A cutter designed to cut both on the periphery and the sides. Usually used in straddle milling operations.

Silicon

A widely-distributed non-metallic element (symbol si) prepared as a dull brown amorphous powder, as shining metallic scales resembling graphite, or as a steel-gray crystalline mass, by heating silica with carbon in an electric furnace.

Silicon controlled rectifier

An electronic device that is generally used in control systems for high-power loads such as electric heating elements or direct current motors. Its operation is like a transistor.

Silicone

Any of various organosilicon compounds containing a silicon-carbon bond; with many physical, chemical, and electrical uses as lubricants, greases, polishes, insulating resins, waterproofing materials, and for the making of special types ofsynthetic rubber

Silicone carbide

Sold under a variety of trade names, and used as a refractory material and as an abrasive. For the machine shop it is used in grinding wheels for non-metallic materials and low tensile strength metals such as aluminum, copper, cast iron, etc.

Silver solder

Solder used by jewelers containing copper and silver.

Simple equation

A mathematical expression of equality between two or more quantities.

Simple machine

Any one of the several elementary mechanical contrivances such as wheel, lever, wedge, screw, or inclined plane. Also basic hand tools such as the hammer or chisel.

Sine (math)

The function of an angle in a right-angled triangle; the ratio of the side opposite that angle to the hypotenuse.

Sine bar

A tool used to locate work to a given angle, or for accurately measuring angles.

Sine spinning

Same process as shear spinning.

Single belting

A belt composed of only one thickness of leather.

Single cut file

A file which has parallel rows of teeth running at a 45 angle across its face, as distinguished from a double cut file which has parallel rows of teeth crossing each other at an oblique angle.

Single thread screw

A screw with but one helix; its pitch and lead are equal.

Single-phase motor

A motor which operates on single-phase alternating current.

Single-stroke header

A cold heading machine in which the punch forces the blank into a die and forms the head in one blow. Single-stroke headers may be of open or closed die types.

Sintering

A method of bonding metal powders by heating them to a predetermined temperature.

Size of weld

Joint penetration in a groove weld.

Skelp

Iron plate or steel from which tubing and pipe are made.

Sketch

An incomplete but suggestive presentation or delineation of something, either graphic, oral, or literary. In machine work a sketch usually means a freehand drawing.

Skew gear

Gears with spiral teeth, used largely on the rear axles of automobiles. They are strong and smooth and quiet in operation.

Skimmer

A piece of iron in a foundry which catches dirt and surface impurities on the surface of molten metal when pouring.

Slab

In steel mills, a slab is a large rectangular piece of steel, the usual shape before entering the rolling mills.

Slabbing cutter

A wide-faced milling cutter usually used in facing operations.

Slag

Impurities fluxed from the cupola in foundry work; in welding, the refuse of splatter from a welding operation.

Slag inclusions

Nonfused, nonmetallic substances in the weld metal.

Sledge

A large, long handled hammer used with both hands.

Sleeker

A tool used by molders to remove rough spots and sand from molds. Also called slicker.

Sleeve

A cylinder which fits over a rod or shaft.

Sleeve

A tapered steel piece which fits on the shank of a drill to permit it to be fitted properly in a spindle with a tapered hole of larger size.

Slicking

Smoothing the surface of molds (foundry work).

Slide caliper

A pocket caliper consisting of a calibrated slide retained in a rule-type beam. A semi-precision tool for quick readings of both inside and outside diameter dimensions.

Slide rest

On a lathe, the dovetailed parts above the saddle which support the compound rest.

Slide rule

A device consisting of a rigid ruler with a central sliding piece, both ruler and slide being graduated in a similar logarithmic scale to permit rapid calculations.

Sliding fit

Same as running fit.

Slip

The difference in speed between the rotor and the stator field as compared to the synchronous speed of a motor

Slip bushing

A jig bushing which is easily removed to permit the use of another bushing with a different bore size.

Slip jacket

A box with an open top and bottom which is placed over a mold in a foundry after the snap flask has been removed.

Slip washer

Same as open washer.

Slip-joint pliers

The most common type of pliers. They may be adjusted to a larger range of opening by sliding a pin connected to one half of the pliers, from one end to the other of a slot in the other half.

Slippage

Loss in work, as in transmission of power.

Slitting

The process of cutting wide sheet metal into lesser widths. Coils of sheet metal from the steel mills are often wider than necessary for their intended use in a stamping plant or sheet metal shop.

Slot velocity

Linear flow rate of contaminated air through a slot.

Slotter

A machine used primarily for cutting slots, grooves, or squaring round holes. A slotting attachment is often used on a milling machine. The cutting tool stroke on a slotting machine is vertical.

Smelting

The process of separating metal from its ore by heat and fluxing agents.

Smoke

An air suspension (aerosol) of particles,

Snap flask

A flask used in foundry work. Designed with catches and hinges to permit its removal after the mold is made.

Snap gage

An inspection gage set at a specified dimension and non-adjustable.

Snips

A common term for hand shears used in sheet metal work.

Snug fit

The closest fit between the two mating parts that can be assembled by hand.

Soaking

In heat treatment of metal soaking is the holding of the metal at a specified temperature until uniform penetration of the heat is accomplished.

Socket

A cavity or an opening specially adapted to receive and hold some corresponding piece or fixture (i.e., a socket wrench is designed to fit over a nut or bolthead).

Solder

A fusible metal or alloy used for joining metallic surfaces or margins, applied in a melted state either as a hard solder, melting only at a red heat, or as a soft solder, melting below a red heat.

Soldering iron

Also called soldering copper, this is a tool which is heated to melt the solder and heat the metals that are to be joined in a soldering operation.

Solenoid

An electromagnetic coil for operating a switch operating armature or plunger.

Solid angle

The angle formed at the vertex of a cone or subtended at the point of intersection of three or more planes.

Solid pellet oxyfuel gas welding

Portable welding system using fuel gas with pellets which produce oxygen.

Solid state

The logic of a computer or machine control unit made solely of solid-state semiconductor components. There are no relays, vacuum tubes, etc.

Solidus

Highest temperature at which a metal or alloy remains a solid.

Sort

To arrange data or items in an orderly sequence by applying specific rules.

Specific heat

The amount of heat necessary to change the temperature of one pound of material 1 degree farenheit.

Speed lathe

A metalworking lathe, not equipped with automatic feeds.

Spelter

An alloy, half copper and half zinc; also the commercial name for zinc ingots.

Sphere

The surface described by a semicircle making one complete rotation on its diameter as a fixed axis. A solid having every part of its surface equidistant from its center. Volume = diameter x 0.5236 area = diameter x 3.1416

Spherical angle

The angle formed at the intersection of two great circles on a sphere; its value is a measure of the difference in direction of the arcs of the intersecting circles.

Spheroidizing

Heating and cooling to produce a spheroidal or globular form of carbide in steel.

Spin

To shape sheet metal by pressure as it revolves in a spinning lathe.

Spindle

A rotating rod, pin, axis, arbor, or shaft, in machine tools, upon which is mounted either the work or the cutting tool.

Spindle speed

The rate of rotation of the machine spindle usually expressed in terms of rpm.

Spiral

A curve formed by a fixed point moving about a center and constantly increasing the distance from it.

Spiral coupling

A type of coupling which engages when rotating in one direction, and disengages when rotating in the other.

Spiral gear

A gear of which each tooth constitutes a part of a helix. Also called screw gear.

Spline

A long key in the form of a flat, straight or involute strip for insertion in a slot or groove between parts or the keyway for such a key.

Spline speed

A shaft with a number of lengthwise grooves or keyways about its circumference designed to make a sliding engagement with mating internal keys on another part to transfer rotation to or from the shaft.

Split bushing

A bushing divided lengthwise into two halves.

Split pulley

A pulley made in halves and bolted together.

Split-phase motor

A single-phase induction motor which develops its starting torque by a phase difference between the start windings and the run windings of the field.

Spoke

An arm of a wheel which connects the rim to the hub.

Spot weld

To join two sheet metal members together, overlapping the parts and welding in spots by pressing the parts together between electrodes and by the heat resistance of the material to an electric current . . . Not used on sheet copper or brass

Spotface

To finish a round indented surface around a drilled hole to give a good seat for a bolthead, nut, or screw surface. Usually not much more than a scraping of the surface.

Spray arc

Gas metal arc process which has an arc voltage high enough to continuously transfer electrode material across an arc in small globules.

Spring chuck or spring collet

A sleeve slotted lengthwise, usually three slots equidistant from each other. Used as a workholding device in lathes, milling machines, etc., It tightens on the work by being forced into a tapered cap which squeezes the slots together

Springback

The degree to which metal tends to return to its original shape or contour after undergoing a forming operation.

Sprocket

Toothlike projections on a wheel designed to engage the links of a chain.

Sprue

The opening or channel through which molten metal may enter into the mold. Also solidified iron which filled the sprue.

Spur gear

The most common type of gear wheel. Its teeth are cut parallel to the direction of rotation.

Square

An instrument having at least one right angle and two straight edges, used to lay out or test square work. A parallelogram having four equal sides and four right angles.

Square measure

144 square inches equal 1 square foot (sq. Ft.); 9 square feet equal 1 square yard (sq. Yd.); 30-1/4 square yards equal 1 square rod (sq. Rd.); 160 square rods equal 1 acre (a); 640 square acres equal 1 square mile (sq. Mi.); 36 square mil

Square root

A number or quantity that, multiplied by itself, produces the given number or quantity; i.e., 4 is the square root of 16.

Square threaded screw

A screw thread whose section is rectangular in form.

Squaring shears

A machine for cutting sheet metal from sheets or for trimming to exact size.

Squeeze period

The interval between the application of pressure and the application of welding current in resistance welding.

Stack

A sequence of memory locations that stores, or stacks, computer words when the computer receives an interrupt request or when instructed.

Stainless steel

A steel alloy made resistant to corrosion and atmospheric influences by the addition of from 12 to 30 percent chromium and other ingredients.

Stakes

Bench anvils of various shapes and sizes used by sheet metal workers for forming and bending sheet metal.

Stand-alone program

A program that can be executed independently of an operating system.

Standard

Any extablished measure of extent, quantity, quality, or value. An accurate example for comparison.

Star drill

A tool for drilling in stone or masonry. The cutting end is starshaped, hence the name, and cutting action is obtained by numerous hammer blows.

Stator

The stationary field coils of a generator or motor.

Stay bolt

A rod threaded on both ends used in boiler work to provide stability and prevent bulging of the plates where the rods are used.

Stay bolt tap

A combination tap and reamer used in boiler work.

Steady rest

A support which may be attached to the ways of a lathe to permit trueing up the work and provide stability for long, slender work.

Steam hammer

A heavy hammer (block of steel) which is actuated by steam. Similar types of hammers are operated by air and hydraulic power.

Steel

A tough alloy of iron containing carbon in variable amounts up to about 2.0%, malleable under certain conditions, and greatly hardened by sudden cooling. Commercial grades are classified on the basis of carbon content.

Steel alloys

Special steels made by adding certain components for special purposes: vanadium to resist fatigue; chromium for resisting shocks; manganese for strength; tungsten as a hardener and heat resistor; nickel for strength and toughness.

Steel belt

Steel belting has been successfully used on pulleys faced with a thin layer of cork, and a 1 steel belt has approximately the same power transmission ability as a 5 leather belt. It is made in thicknesses varying from 0.008 to 0.035 an inch.

Steel casting

A part made from cast iron and scrap steel which have been melted together and poured into a mold; also a machine construction material.

Steel rule

A rule made of steel.

Steel square

A small square used by machinists or the larger one used by carpenters. It consists of two beams set at right angles to each other. The one most commonly used in the machine trade consists of a heavy beam and a metal blade at right angles,

Stellite

Haynes stellite is a non-ferrous alloy of cobalt, tunsten, and chromium, much used as cutting tools in the machining of metal.

Steradian

The unit of measurement for solid angles which, on a sphere, encloses a surface equivalent to the square of the radius.

Stiction

The combination of adhesion (sticking) and friction which must be overcome to move a machine member from rest.

Stillson wrench

The common pipe wrench. Stillson is the name of the inventor.

Stock

Term used when referring to material. Term used when referring to screw supply. Term used when referring to amount of material being removed when machining.

Stock and die

A die for cutting threads manually, and (stock), the handles or levers used to rotate the die.

Stone

To remove small burrs with an abrasive hand tool. The tool itself.

Stop

A piece attached to some part to prevent motion past a certain point.

Storage

In data processing, a device into which data can be entered, in which it can be held, and from which it can be retrieved at a later time. In production, an area or device in which parts or materials may be stored for later use.

Storage medium

Any device or recording medium into which data can be stored and held until some later time, and from which the entire original data can be obtained.

Stored-program numerical control

Usually the same as cnc. The distinguishing feature is an internal membory that can be altered by receiving new instructions. The physical configuration is not altered by programming.

Stove bolt

The same as a machine screw, except that it is supplied without a nut.

Straddle milling

Using two or more milling cutters to perform several milling operations simultaneously.

Straight angle

An angle of 180 generated by two straight lines extending in opposite directions from the vertex.

Straight cut control system

A system in which the controlled cutting action occurs only along a path parallel to linear, circular, or other machine ways.

Straight edge

A precision tool for checking the accuracyof a flat surface

Straight fluted drill

Same as farmer's drill.

Straight peen hammer

A hammer with a wedge-shaped peening edge which runs parallel to the handle.

Straight-shank drill

A drill with a straight cylindrical shank. Customarily found on drills of less than ½ inch diameter. Used in collets and self-centering chucks.

Straight-shank milling cutter

An end mill. Usually used in routing and die work in profiling machines.

Strain

A measure of the change in shape or size compared to the original dimensions

Strain

Reaction of an object to a stress.

Stress

Heating of a metal object to a suitable temperature and holding it at that temperature for a proper length of time to reduce internal residual stresses in the part.

Stress relieving

Heating to a suitable temperature, holding long enough to reduce residual stresses and then cooling slowly enough to minimize the development of new residual stresses.

Stretch form

The process of forming shapes with large curvatures by stretching sheet metal over a form of the desired shape.

Striking off

Leveling the surface of a mold in a foundry with some type of bar.

Strip

The removal of threads from a bolt, etc., Through wear or excessive pressure.

Stripper

A device used on presses to prevent the punched metal from lifting with the punch.

Stripping plate machine

A machine in a foundry which strips patterns through a plate.

Stroke

The forward motion in its entire length of a worktable or a toolhead of a reciprocating action machine tool (for example, the stroke of a shaper tool, or a planer table).

Stub's gage

Also known as the birmingham gage. This wire gage has been superceded by the imperial wire gage as a standard.

Stub-gear tooth

A type of involute tooth with a pressure angle of 20 . The addendum and dedendum are both shorter than in the standard tooth. Often used for automobile drives.

Stud gear

Same as intermediate gear.

Stud-bolt

A cylindrical fastener similiar to a bolt, but with no head, and having threads on both ends.

Stuffing box

A chamber through which valve stems or piston rods pass. It is filled with packing to prevent leakage.

Submerged arc welding

Widely used automatic process in which the direct current arc from a bare welding rod is blanketed under a flux. The flux, in granular form, is fed automatically to the welding area.

Subroutine

A portion of the total nc program, stored in the computer's memory, and available upon call to accomplish a particular operation, usually a mathematical calculation.

Suction lift

Exists when the source of supply is below the center line of the pump.

Suction pressure

The pressure read at the inlet side of a pump or compressor.

Super finish

A finish where surface irregularities have been reduced to a minimum to produce exceptionally long-wearing and smooth surfaces; often done by honing or lapping operations.

Superficial rockwell hardness test

Test for determining surface hardness of thin sections or small parts.

Supplement of an angle

The difference between the given angle and 180 ; i.e., a given angle of 100 has a supplement of 80 .

Supplementary angle

One of two angles whose sum is a straight angle.

Surd

An irrational number or quantity, especially an indicated root that can only by approximated, as the square root of 2.

Surface gage

A tool used primarily for layout work in the machine shop. It is not calibrated, and consists of an adjustable scriber mounted on a heavy base.

Surface grinder

A grinding machine designed for the grinding of flat surfaces. It usually has a worktable which contains a magnet to hold the work without clamps or other workholding devices.

Surface grinding

The grinding of flat metal surfaces.

Surface hardening

Same as case hardening.

Surface plate

A layout or inspection plate of granite or iron whose surface has been scraped, lapped or ground to a precise degree of smoothness.

Surface roughness

Roughness refers to the finely spaced irregularities produced in fabricating a part. The height of the irregularities is rated in microinches.

Surface speed

On cylindrical work, as in a lathe, surface speed is calculated in feet per minute (circumference of the work in feet, multiplied by the number of revolutions per minute). Surface speed may also refer to work moving in a straight line.

Surface treatment

Surface treatment is any treatment which changes the chemical, physical or mechanical properties of a surface.

Surfacing

Depositing material on a surface to obtain desired properties or dimensions.

Swage

To change the shape of a piece of metal by hammering, rolling or otherwise forcing without cutting.

Swage block

A heavy block of iron having various shaped holes and grooved sides, used for shaping objects of large size.

Sweat

To solder metal pieces together by covering two surfaces with solder and then clamping and heating sufficiently to melt the solder.

Swing

The distance from the center of a lathe spindle to the nearest point on a way of the machine; the diameter dimension of the largest piece of work which the machine will accommodate.

Switch

A mechanical device for opening or closing a circuit.

Swivel vise

A bench vise which may be swiveled on its base to bring work into a better position.

Symbol

A character or mark used as an abbreviation.

Symbolic representative

Use of a symbol such as an alphabetic or numeric character, punctuation mark, or other visual figure designed to represent a more complex piece of information.

Synchronize

To lock one element of a system into step with another.

Synchronous motor

An a.c. motor whose rotor is activated by d.c. it is charactertized by it's constant speed.

Synchronous speed

The speed at which the rotating field in an a.c. motor revolves.

System simulations

Computer system simulation is a technique used to predict system performance by exercising a model of the system hardware/software over time. Simulation based on well-planned experiments representative of the real-world environment will pr

Systems analysis

The analysis of an activity to determine precisely what must be accomplished and how to accomplish it.

T-bolt

A bolt with a long, narrow head designed to fit into the t-slots of the worktables of milling machines, drill presses, etc.

T-joint

Joint formed by placing one metal against another at an angle of 90 degrees to form a t shape.

T-slot

An undercut, recessed slot in the table of a milling machine, drill press, planer and similar machines, designed to receive the heads of t-bolts, which may be slid along the slots to a desired position for clamping work, etc.

T-slot cutter

A milling cutter used for cutting the undercut or wide portion of t-slots.

T-square

A draftsman's tool shaped like a t. The blade is from 2 to 3 inches wide, and from one to five feet long. It is solidly attached to the head, which is thicker than the blade, at right angles.

T-wrench

A socket wrench shaped like the letter t. The handle is at right angles to the body or shank.

Tab

A nonprinting spacing action on typewriters and tape preparation devices.

Tachometer

A device for indicating the speed of rotation, as a shaft.

Tack weld

To fasten two pieces together by welding small spots at intervals to hold the position while the welding is being done. It is done when the amount of work does not warrant the construction of a jig.

Tackle

The pulleys or blocks along with the chain or rope which comprise the parts of a type of hoisting device.

Tail print

In pattern making, an extension on a core print to permit the easy withdrawal of the pattern from the mold.

Tailstock

The movable head or stock of a lathe which is positioned at the opposite end of a lathe from the headstock. It slides on the ways, and may be adjusted sideways for true centering.

Tailstock spindle

The sleeve or spindle which carries the dead center in a tailstock; also used to house various machining tools such as drills, taps, reamers, etc.

Taking up

The adjustment of parts to remove looseness caused by wear, such as the tightening of a gib in a dovetail.

Talc

Soapstone; often used in certain lubricants.

Tallow

Refined animal fats used in greases and lubricants.

Tamping

A term used by molders to refer to the ramming up of sand around a pattern.

Tang

The flattened end of the shank of a drill, reamer or other similar tool which is designed to assist in the removal of the tool from its sleeve or socket.

Tangent

Touching a line or surface at a point without intersecting.

Tank

Thin walled container of fluids or gases.

Tantalum

A metal which is increasingly used in the aerospace industries because of its ability to withstand high temperature, from 2500 to 4000 f.

Tap (1)

Tool for cutting an internal screw thread. To cut threads in a hole by the use of a tap. Taper, plug, and bottoming taps are three tools identical in thread and form and size, the only difference is the chamfer at the end.

Tap (2)

Connection made to a coil at a point other than its terminal.

Tap hole

The hole in the breast of a cupola through which molten metal is drawn.

Tap remover

A tool designed to remove the remains of a broken tap from a hole.

Tap wrench

A wrench designed to grip a tap in the center of the wrench, the handles extending in both directions from the tap. This design makes it easier to balance the pressure in hand tapping, and keep the tap aligned with the hole.

Tape, measuring

A flexible measuring scale usually made of thin metal, or linen or cotton, ordinarily six feet or longer, and contained in a metal case into which it is wound when not in use.

Taper

A uniform and gradual decrease in size; cone-shaped.

Taper attachment

An attachment for a lathe which permits uniform and precise taper turning or boring with the use of automatic feed.

Taper gage

A gage for testing the accuracy and the degree of a taper.

Taper per foot

The accepted way of expressing the amount of taper; the increase in the diameter is expressed in inches, the length is expressed in feet; for example, the standard morse taper is 5/8 inch diameter increase in a foot of length.

Taper pin

A metal pin, solid, cylindrical, and tapered. They range in size from a #1, which is .156 inch diameter at the large end and ¾ to 1 inch long, to the #10 which is .706 inch diameter at the large end and from 1 ½ to 6 inches long.

Taper pin drills

Drills designed to drill holes in metal to accommodate taper pins. They have serrated edges and a taper of ¼ inch per foot.

Taper reamer

A straight fluted reamer designed to cut a taper in a straight hole to accommodate a taper pin.

Taper turning

On a conventional lathe, it is the taper turning of a workpiece by setting over the tailstock or by the use of a taper attachment. I

Tapered spindle

The spindle of a machine tool which contains a tapered recess designed to receive the tapered shank of a tool or center or workholding device.

Tapered-shank drill

A drill with a tapered shank designed to fit into drill press spindles, etc., Without using chucks or collets. Drills with tapered shanks are usually above ½ inch in size and the standard taper adopted for them is the morse taper of 5/8

Tapped faceplate

A faceplate which has tapped (threaded) holes instead of or in addition to the usual slots.

Tapper tap

A special tap used in tapping machines.

Tapping

Cutting threads on the inside circumference of a hole by using a tap.

Tapping bar

A long metal bar used in a foundry to open the cupola so that the molten metal may be drawn off.

Tapping machine

A machine designed for small parts thread cutting on a production basis. It automatically feeds and rotates a tap to cut the threads then reverses the rotation of the tap to back it out.

Tee

A pipe fitting for changing the direction of a pipe run, or for connecting pipes of unequal size.

Telescoping

To drive or slide together so that one part fits into another like the sections of a small telescope.

Telltale

A homemade device to indicate to a machine operator when a machining or setting-up objective has been accomplished.

Temper

To reheat quenched, hardened steel to some predetermined temperature for a certain length of time and chill by suitable means. This treatment removes stresses in the steel which make it brittle, and adds toughness, reducing the danger of breakage.

Template

A flat pattern upon which holes, shapes, cuts, etc., Are laid out, and from which the work is marked for fabrication. On a tracer machine tool, the template serves as a guide for a stylus which controls the contouring movement of the cutting tool

Tensile strength

The resistance of a material to forces of rupture and longitudinal stress, usually expressed in pounds or tons per square inch.

Tension

A pulling force which tends to make a member longer than it naturally is.

Tenth

A term commonly used in machining operations meaning 1/10 of 1/1000 or .0001. Not to be confused with .1 (1/10).

Terminal

A point of electrical connection.

Theorem

A truth capable of demonstration; a proposition that has been proved or is assumed to be true.

Theory

Abstract knowledge as opposed to the practice of it.

Thermit welding

A pressure welding process in which the heat is obtained from liquid products of a thermit reaction.

Thermocouple

A device used in pyrometers for measuring extreme heat.

Thermostat

A bimetal actuated switch to used to control an electrical circuit based on temperature.

Thickness gage

Fixed gages in leaf form, ground to decimal dimensions, and often used to check clearances between mated parts.

Thread

The spiral ridge of a screw. To make a screw thread.

Thread cutting screws

See self tapping screws.

Thread gage

A ring or plug type gage to check the fit of a thread.

Thread miller

A milling machine designed for the cutting of worm gears and screw threads.

Thread rolling

A technique for manufacturing screw threads which produces a stronger, less expensive thread  than traditional methods. The metal blank is rolled between two grooved die-plates exerting enough pressure to raise the metal and form the thread.

Threading

The cutting of screw threads.

Threading tool

A lathe cutterbit, ground to the profile of the thread to be cut (chased).

Threads per inch

The diameter and the threads per inch are the two factors which express thread size. The number of screw threads in an inch of length is standardized, generally in two categories; coarse and fine.

Three dimensional

Presentation in graphical form of three-dimensional objects. Various types of projections exist to reduce 3-d to 2-d drawings (isometric, perspective, etc.)

Three- (or four-) fluted drills

Drills used to enlarge already existing holes, sometimes used as a roughing reamer. They are not suitable for originating a hole in solid metal.

Three-square file

A term sometimes applied to a three-cornered file.

Three-wire method

A method of measuring the pitch diameter of a screw thread. It is extensively used and quite accurate. Two wires are placed in adjoining threads on one side, and one wire inthe thread diametrically opposite. A measurement is then taken over the wires.

Threshold limit values (tlv)

The values for air borne toxic materials which are refered to in the control of health hazards.

Throat of a fillet weld

Distance from the weld root to the weld face.

Thrust bearing

A bearing which receives the longitudinal pressure of a shaft.

Thrust collar

A collar turned or attached to the body of a shaft for the purpose of absorbing end play.

Thumb nut

Same as wing nut.

Thumbscrew

A screw with a flattened head for easy turning with thumb and forefinger.

Tight pulley

A pulley that is attached to its shaft, as compared to a pulley that rotates on a shaft, which is stationary.

Time standard

A predetermined time allowance for performing a given operation. Usually based on an estimate of production quantity and productivity.

Timing analyzer

A computer program that monitors and prints execution time of all program elements (functions, routines, and subroutines).

Tinning

The coating of a soldering iron with solder prior to its use. Also in tin-plate manufacturing, the process of coating metal plate with tin.

Tinplate

A thin sheet of metal coated with tin.

Tinsmith

A skilled workman who makes articles from thin metal.

Tinsnips

The common hand shears used for cutting thin metal.

Tip

End of the torch where the gas burns, producing the high temperature flame.

Tir (total indicator reading)

The difference between the maximum and minimum indicator readings obtained.

Titanium

A metal nearly as strong as steel, but only about half the weight. It has good temperature and corrosion resistance.

Toe

The edge of a flange on a metal bar.

Toe crack

Base metal crack at the toe of a weld.

Toe of weld

Junction between the face of a weld and the base metal.

Toggle

A double joint having a central hinge like an elbow.

Tolerance

The total permissible amount by which a dimension may vary above or below a specified size.

Tongs

A long-handled tool built on the principle of pliers, used for picking up or holding metal for forging or heat-treatment.

Tool function

A command identifying a tool and calling for its selection either automatically or manually. The actual changing of the tool may be initiated by a separate tool-change command.

Tool offset

A correction for tool position parallel to a controlled axis.

Tool steel

Any of a variety of high-speed or carbon steels which may be hard enough to serve as metal cutting tool bits or cutters.

Tool tip

A small piece of cemented carbide, properly shaped, which may be welded, brazed, or clamped on a steel shank and used for metal cutting.

Toolbit

A small piece of high speed steel appropriately ground and shaped to cut metal on a lathe. Prior to shaping and grinding, it is called a tool blank.

Toolcrib

An area set aside in a machine shop for the storage and dispensing of tools and supplies.

Toolhead

The assembly on planers and shapers, etc., Into which the tool bit is inserted. It may be rotated or adjusted for height, and then firmly fastened for cutting operations.

Toolmaker

A skilled workman trained in the making of jigs, fixtures, tools, etc.

Toolmaker's clamp

A small clamp consisting of two parallel jaws, adjusted by two threaded rods with knurled handles; basic design is similar to a woodworker's screw clamp.

Toolpost

A circular metal post with a clamping screw in the top, used to position and firmly hold the toolholder on a lathe compound rest assembly.

Toolpost ring

A metal ring with a concave face which encircles the toolpost and forms a seat for the toolpost rocker.

Toolpost rocker

A small metal piece shaped like the segment of a circle, which is positioned in the slot of a toolpost and upon the concave face of the toolpost ring. The toolpost is positioned upon it and may be raised or lowered by rocking the rocker.

Toolroom

A department where dies, jigs, fixtures, and tools are made and repaired.

Tooth face

The part of a tooth of a milling cutter which forms the rake, and over which the chip passes as it is removed from the work.

Torque

Twisting force set up by or in a revolving shaft (torsion).

Torque wrench

A wrench that contains a gage which indicates the amount of torque pressure. Some torque wrenches are designed to disengage when the torque required to turn a bolt or nut reaches a certain value.

Torsion

Twisting motion resulting in shear stresses and strains.

Tote boxes or pans

Metal boxes used in industry to store or carry small parts. They are tapered on the sides usually, so they will fit into each other and may be stacked for storage.

Touch up

Positioning of the tool against the work before setting the depth of cut.

Toughness

Metal's ability to absorb energy and deform prior to breaking.

Tracer

A tracer lathe; a lathe fitted with an attachment wherein a pattern and a stylus control the contouring movements of the cutter. Also an apprentice or aid whose job it is to make tracings of a draftsman's drawings.

Tracing

A drawing which has been transferred to a transparent material for quantity reproduction.

Tracing paper

Thin semi-transparent paper used in the reproduction process of blueprinting.

Track

A path parallel to the edge of a tape along which information may be stored by presence or absence of holes or magnetized areas.

Trailing zeros

Redundant zeros added to the right side of a number to fix the position of the decimal point.

Train

A series of meshed gears.

Trammel

A beam compass used for large work.

Tramming

Indicating a cylindrical surface of a part in such a manner so as to centralize the surface with the spindle of the machine.

Transacting processing

The entering of records or events into the information system when each event occurs. Generally, only relevant data is entered, with accompanying program or job control language statements.

Transaction

An event (sale, order, payroll change, etc.) Of interest to the enterprise which controls the information system. Also, a computer-processable record of that event.

Transducer

A device which converts one form of energy to another form of energy. In numerical control design, it usually applies to a device for converting rotary motion into a varying sine-wave voltage.

Transfer calipers

Calipers designed so that a measurement may be obtained, and if the work is of such a nature that the caliper setting must be changed to remove them from the work, they can be reset to the exact setting after removal.

Transformer

A device containing two or more coil circuits. Energy is transferred from one coil to another by electromagnetic induction.

Transistor

An electronic device able to control large electric current flow by a small control voltage/current.

Translate

To transform statements from one computer language to another. In computer graphics, to move a display image on the display surface.

Translator

A computer program written to convert source (assembly) code associated with one computer system into equivalent source (assembly) code on another computer system.

Transmission

An arrangement of gears by which variations of speed ratios, and forward and reverse motion are obtained.

Transport (conveying) velocity

Minimum air velocity required to move the particulates in an air stream.

Transpose

To transfer a term from one side of an equation to another, with a changed sign, so as not to destroy the equality of the members.

Tranversal

A straight line intersecting a system of lines. In a machine shop, it refers to the travel of a milling machine table when going toward or away from the machine column.

Trapezium

A four-sided geometrical figure with no parallel sides.

Trapezoid

A four-sided geometrical figure with two parallel sides.

Traveling crane

An overhead crane (hoist), usually operated by electric power, which can travel longitudinally or transversely.

Treadle

A foot pedal designed to operate a machine.

Trepanning

Cutting a circular groove around a hole.

Triangle

A plane geometrical figure having three interior angles and three sides.

Triangular scale

A rule or scale used by draftsmen which has three edges, each edge having two sets of calibrations, one of them actual measurement, the other five being scale or representative measurement.

Trigonometry

The branch of mathematics pertaining to the relations of the sides and angles of triangles, and of the methods of applying these relations in the solutions of problems involving triangles. Many of these solutions are useful in drafting and other trades.

Trimetric projection

A three dimensional geometric projection in which each dimension is measured on a separate scale and according to arbitrarily assigned angles.

Trimming dies

Dies used to remove excess metal left around the edges of formed or drawn work.

Trip hammer

A power hammer which has a tripping mechanism that causes the hammer to drop.

Trolley

That part of a hoist which permits the hoist to travel on a track or beam.

Troubleshoot

To search for the cause of a malfunction or erroneous behavior in order to remove the malfunction. Same as debug.

True

On center.

Trunnion

One of two opposite supporting lugs or projections from the side of an object, which permits it to be turned as on an axis; i.e., the cylinders of some engines oscillate on trunnions.

Try square

A tool used by machinists to check work for squareness, and for laying-out. Sometimes called a solid square, it is usually precisely made to a high degree of accuracy.

Tumble

To whirl in a revolving cask as a means of cleaning and polishing small castings and forgings by friction. Sometimes additional polishing agents such as balls, sawdust, scraps, etc., Are added.

Tumbler

A barrel-shaped rotating container in which parts are tumbled to clean them of scale and sand; also called a rumbler.

Tumbler gear

An intermediate gear in a train whose function is to reverse the direction of the driven gear.

Tungsten

A metal used in making high speed steel.

Turn

To shape while applying a cutting tool while the work revolves and the tool travels on a path parallel to the axis of the work.

Turnaround time

The elapsed time between submission of a job to a computing center and the return of results.

Turnbuckle

A type of coupling designed to regulate the tension of rods or cables it connects.

Turning machine

A machine used in sheet metal work to prepare the edge of shaped metal objects like pails, funnels, etc. To receive a wire.

Turnkey system

A term applied to a computer system whereby a supplier has total responsibility for building, installing, and testing the system, including hardware and software.

Turnover

The number of times inventory is replaced during a time period.

Turret lathe

A production lathe with a revolving tool head which holds several tools and makes possible the rapid succession of operations.

Tuyere

Opening in a blast furnace through which air is forced to support combustion.

U-bolt

A bolt shaped like the letter u, and threaded on both ends; sometimes called a clip.

U-clamp

A bar of steel shaped like the letter u, and used as a clamp.

Ultimate compressive strength

Most compressive stress that a material can withstand.

Ultimate strength

Greatest conventional stress, that a material can stand.

Ultrasonic

Mechanical vibrations with a frequency above the range of human earing.

Ultrasonic grinding

A process in which the grinding wheel is vibrated at ultrasonic speeds, reducing power requirements, lowering the grinding temperatures, providing greater grinding ratios, and improving work finish.

Ultrasonic testing

Nondestructive testing method which transmits and receives high frequency sound through tge material being inspected.

Ultrasonic welding

Process using high sound frequencies to produce metal fusion.

Ultraspeed welding

A resistance welding process, wherein two or more welding electrodes are in simultaneous contact with the material to be welded, with the welding current commutated successively between the welding electrodes by means of a communtating device.

Ultraviolet rays

Energy waves that come from electric arcs and welding flames at a frequency that the rays fall into the ultraviolet light spectrum.

Underbead crack

Crack in the base metal near the weld and beneath the surface.

Undercut

A cut leaving an overhanging edge.

Undershoot

The tendency of a machine to round-off corners of a programmed path as a result of servo-lag.

Unified threads

A series of screw threads that have been adopted by the united states, great britain and canada to provide interchangeability of parts.

Unilateral tolerance

An allowable variation from a basic dimension, but in only one direction, either oversize or undersize (plus or minus), but not both.

Union

A connection for pipes, often called a coupling.

Unit

A device having a special function or is a basic element.

United states form thread

A screw thread with the same shape as the u.s.s. national coarse, but has a different pitch.

Universal

Adapted or adaptable to a great variety of uses, shapes, or motions. A milling machine table, for example, is called a universal when it may be swiveled, as well as having the more common movements of up/down, back/forth, and in/out.

Universal chuck

A chuck on which all jaws move simultaneously at a uniform rate. It automatically centers round stock, or stock whose number of sides is equally divisible by the number of jaws.

Universal grinding machine

A grinding machine which has a table, headstock, and wheelhead, all of which may be swiveled. The machine is very versatile in that internal, external, face and surface grinding may be accomplished with it.

Universal milling machine

A milling machine with a table that has all standard movements, but also swivels.

Universal motor

A series motor which operates on either alternating or direct current.

Unshielded carbon-arc welding

A carbon-arc welding process in which no shielding medium is used.

Unshielded metal-arc welding

A metal-arc welding process in which the electrode used is either very lightly coated, or bare.

Upset

To shorten and thicken a metal bar or shaft by hammering on one of its ends.

Upset butt welding

A resistance butt-welding process in which the potential is applied after the parts to be welded have been brought in contact. The heat is derived principally from the resistance.

V-belt

A belt with a v-shaped section for use on grooved pulleys. They have less tendency to slip than flat belts.

V-block

Rectangular or square shaped steel block with a 90-degree v accurately machined through its center. It usually is provided with a clamp for holding round stock for accurate machining operations.

V-thread

Sometimes called a sharp v-thread, it has a v-shaped section and is sharp on the top and bottom; in all other respects it is similar to the u.s.s. thread which has a flat on the top and bottom of the thread equal to 1/8 of the pitch.

Vacuum

A space from which air, liquid or any other matter has been exhausted.

Valve

A device for regulating the flow of gas or liquid through pipes.

Vanadium

A silver-white metallic element used in making alloy steel, particularly steel for parts which need to withstand considerable shock, such as automobile axles. The alloy contains about 0.10 to 0.15% vanadium, can be forged readily, but mustbe heated slowly

Vanishing point

In perspective drawing, the point at which all parallel receding lines meet.

Vapor

The gaseous form of substances which are normally in the solid or loquid state and whose state can be changed by increasing pressure or decreasing temperature.

Variable

A quantity that may change in value while others remain constant.

Variable block format

A format which allows the number of words in successive blocks to vary.

Variable costs

An operating cost that varies directly with production volume; for example, materials consumed, power, direct labor, sales commissions, etc.

Variance

The difference between the expected or planned, and the actual.

Vector

A directed line segment and in computer graphics, is always defined by its two end points. Vectors may be of two types; i.e., absolute and relative, and may be drawn in several textures and intensities, or blanked.

Vector feedrate

The resultant feedrate which a cutter or tool moves with respect to the work surface. The individual slides may move slower or faster than the programmed rate, but the resultant movement is equal to the programmed rate.

Vee or veeway

Ground and/or scraped ways which serve as a guide for movable parts of a machine, as the tailstock or carriage on a lathe. It is shaped like a v, and may be raised or sunken.

Velocity

Distance divided by time; in machine work it is expressed in feet per second or per minute.

Vents

Narrow openings in molds to permit the escape of gasses which have been generated during pouring.

Verify

To check, usually automatically, one typing or recording of data against another in order to minimize human and machine errors in the punching of tape or cards.

Vernier

A movable auxiliary scale used to obtain fractional parts of a fixed scale's subdivisions; the complete instrument. The vernier principle is used on a variety of tools, among them the depth gage, height gage, bevel protractor and gear-tooth caliper.

Vertical

Upright or perpendicular.

Vertical boring mill

A machine tool with a circular, revolving table, and a toolhead capable of both vertical and horizontal feed movements.

Vertical milling attachment

An attachment which may be connected to a horizontal milling machine to permit vertical milling operations.

Vertical milling machine

A milling machine with a vertical spindle.

Verticle turret lathe

A variation of the turret lathe which has a vertical spindle and a large worktable instead of the conventional chuck.

Vickers (hardness test)

The vickers test is similar in principle to the brinell test. The standard vickers penetrator is a square-based diamond pyramid having an included point angle of 136 degrees. The hardness number is based upon the diagonal length of the sququare impression

Vise

A mechanical device for holding work. It consists usually of a fixed and a movable jaw, the latter activated by a strong screw (generally a square or buttress thread). They are made in many variations.

Vise clamps

Often called soft jaws, vise clamps are usually hand-made from pieces of thin copper or brass sheets, cut and formed to slip over the steel jaws of a vise to prevent bruising the work.

Vixen file

A flat file with curved cuts, very good for use on soft metal.

Volt

The unit of measurement of electromotive force.

Voltage regulation

A measure of the ability of a generator to maintain constant voltage output while adding or removing a load.

Wall bracket

Any bracket attached to a wall or post and used as a support; frequently a shaft hanger attached as above.

Warding file

A flat, thin file used by locksmiths.

Warping

A distortion of a foundry casting caused by unequal strains in cooling.

Washer

A small, flat ring of metal or other material used to relieve friction or prevent motion, when placed under a nut or bolthead.

Waste

The cotton waste used in shops by oilers, maintenance men, etc., For cleaning. It is composed of soft, fine, cotton fibers matted together and is very absorbent. It is quite inexpensive since it is made from the refuse of cotton mills.

Water manometer

Used to measure in inches of water.

Watt

The unit of power measurement.

Watt-hour

The unit of energy measurement equal to one watt per hour.

Waviness height

Refers to surface irregularities spaced too far apart to constitute roughness. Both height and width of waviness are rated in inches.

Ways

Flat or v-shaped bearing surfaces on a machine upon which other parts of the machine may ride, as the ways of a lathe upon which the tailstock rides.

Weak sand

Foundry sand that has such a small percentage of clay that it does not hold together well; therefore, not suitable for the usual casting processes.

Web

A thin metal strip which connects and adds strength to two parts of a forging, casting, etc.

Wedge

A piece of material tapering to a thin edge. It is used for producing a strong pressure and is considered one of the basic simple machines.

Weld bead

Deposit or row of filler metal from a single welding pass.

Weld crack

Crack in weld metal.

Weld metal

Fused portion of base metal or fused portion of the base metal and the filler metal.

Weld nugget

Weld metal in a spot, seam, or projection weld.

Weld pass

Single progression of a weld or surfacing operation.

Welding

The joining of pieces of iron or steel by fusion. It is usually accomplished by oxyacetylene, electric or forging.

Welding rod

A manufactured rod of a variety of metallic compositions used to flow metal into joints being welded. Made in various sizes ranging from ¼ to ½ inch in diameter, and about two feet long.

Welding transformer

A step-down transformer used to produce sufficient instantaneous current to fuse metals in contact, through which it flows.

Weldment

Assembly of component parts joined together by welding.

Wheel dresser

A device for truing the periphery of a grinding wheel, which simultaneously removes foreign matter which has accumulated on the face of the wheel.

Wheel hub

The center, or boss of a wheel from which spokes radiate, and which is bored to receive the axle.

Wheel lathe

A lathe designed for machining wheels. It usually has a deep gap and a short bed.

Wheel truing

In reference to a grinding wheel, it means to dress the wheel until it is almost perfectly round and in balance.

Whetting

Rubbing a tool on an oilstone to improve the cutting edge of the tool.

Whitney keys

Square bar keys rounded at both ends.

Whitworth thread

The standard english thread, having an included angle of 55 and rounded crest and root (top and bottom of thread).

Wick-feed oilers

A reservoir of oil with a wick immersed in it. Oil absorbed by the wick is dispersed to the bearing.

Wiggler

A device used by machinists to accurately align a drill, end mill or similar tool to a center punch layout mark, or similar set-up operations. It consists of a short, sharply pointed metal rod mounted in a ball joint which is placed in a chuck or collet.

Winch

A device like a spool about which cables are wound or unwound. Usually used for lifting or pulling heavy objects.

Windless

Same as winch.

Windup

Lost motion in a mechanical system which is proportional to the force or torque applied.

Wing nut

A nut with projections attached which make it possible to apply maximum pressure with the thumb and forefinger. Not designed to be used with a wrench.

Winged dividers

Dividers which have a flat metal wing attached to one leg and projecting through a slot in the other leg. A setscrew in the slotted leg permits them to be locked in a desired position.

Wire brush

A hand brush which has small wires in place of bristles. Useful for removing rust and other strongly resistant foreign matter from surfaces.

Wire drawing

The process by which wire is made, as by drawing metal through a hole in a steel plate.

Wire gage

A notched plate, each notch opening a standard sheet metal and wire size. Most common standards used are the united states standard steel wire gage and the american gage or brown & sharpe's gage, which are used for copper and nonferric metals.

Wired edge

In sheet metal work, an edge that has been strengthened by being rolled over, and enclosing a piece of wire.

Wiring machine

A machine used in sheet metal work to crimp the metal around the wire after it has been positioned in the turning machine for producing wired edge products.

Woodruff key

A key in the shape of a half-moon, used to prevent motion of a pulley on a shaft, etc.

Work cell

The most basic unit of a work center.

Work center

An administrative or accounting subdivision of a department. A specific production facility which may consist of one or more persons or machines.

Work elements

In process planning, it is a single task to be performed that cannot be subdivided. For example, drill, mill, deburr, plate, weld, etc.

Work hardening

The hardening of metal while being worked, as in hammering.

Work hardness

The increase in hardness that develops in metal as the result of cold forming.

Work in process

Product in various stages of completion throughout the production cycle, including raw material that has been released for initial processing and completely processed material awaiting final inspection and acceptance as finished product

Work measurement

An analytical approach to establish labor time standards; the work content or each work element is measured by timing and judgment.

Work mounting surface

That part of a table or bed on which part of a tool fixture is mounted, exclusive of any cooling and/or chip trough.

Work place

An assigned location where a worker performs fabrication or assembly of materials or parts through manual or automatic means.

Working depth

The depth of a tooth from addendum line to clearance line (the total depth minus the clearance).

Working drawing

A drawing which provides the necessary information to make and/or assemble a mechanism.

Working gages

A term applied to gages used by workers as distinguished from gages used by inspectors, or master gages.

Worklead

Electrical conductor which carries the current between the welding machine and the workpiece.

Workpiece

Any part in any stage of manufacture prior to its becoming a finished part.

Worm gearing

Gearing composed of worms and worm wheels.

Worm threads

A thread with a 29-degree included angle, similar to an acme thread but deeper.

Wrecking bar

A steel bar with one end drawn to a thin edge, the other curved and ending in a claw. They are usually from one to two feet long.

Wrench

A tool used for exerting a twisting strain, as in tightening a nut or bolt. They are made in many sizes and designs, most widely known are the pipe wrench, box wrench, adjustable wrench, monkey wrench, socket wrench and open-end wrench.

Wringing fit

A class five fit between mating parts.

Wrought

Beaten or hammered into shape.

Wrought iron

Iron which has had the major portion of its carbon removed, also foreign elements which would reduce its workability.

Yield point

The lowest stress to which a material or body can be subjected and at which stran increases without an appreciable or proportionate increase in strees.

Yield strength

Stress value in psi or kpa at which a specimen assumes a specified limit.

Zero

The point from which all coordinate dimensions are programmed in an absolute system.

Zero floating

A characteristic of a numerical machine tool control permitting the zero point on an axis to be established readily over a specific range. The control retains no information on the location of any previously established floating or movable zeros

Zero offset

A characteristic of a numerical machine tool control permitting the zero point on an axis to be shifted readily over a specified range. The control retains information on the location of the permanent zero.

Zero offset point or position

The point to which zero on the machine is shifted to absolute zero.

Zero reset

The ability to realign automatically each axis slide to the zero or target point by pressing a button when the slides are brought within close proximity of the target point.

Zero shift

Same as zero offset except that the control does not have a permanent zero.

Zyglo

A fluorescent penetrant inspection technique for detecting flaws in nonmagnetic metals.