home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Explore the World of Soft…e: Engineering & Science
/
Explore_the_World_of_Software_Engineering_and_Science_HRS_Software_1998.iso
/
programs
/
dies
/
tsa_a.exe
/
TSA_4.EXE
/
G1910.215
< prev
next >
Wrap
Text File
|
1994-11-01
|
42KB
|
671 lines
G1910.215
Starting with: 1910.215 - Abrasive wheel machinery.
1910.215 Abrasive wheel machinery.
(a) General requirements-
(1) Machine guarding. Abrasive wheels shall be used only on machines
provided with safety guards as defined in the following paragraphs of
this section, except:
(i) Wheels used for internal work while within the work being ground;
(ii) Mounted wheels, used in portable operations, 2 inches and smaller in
diameter; and
(iii) Types 16, 17, 18, 18R, and 19 cones, plugs, and threaded hole pot
balls where the work offers protection.
(2) Guard design. The safety guard shall cover the spindle end, nut, and
flange projections. The safety guard shall be mounted so as to maintain
proper alignment with the wheel, and the strength of the fastenings
shall exceed the strength of the guard, except:
(i) Safety guards on all operations where the work provides a suitable
measure of protection to the operator, may be so constructed that the
spindle end, nut, and outer flange are exposed; and where the nature
of the work is such as to entirely cover the side of the wheel, the
side covers of the guard may be omitted; and
(ii) The spindle end, nut, and outer flange may be exposed on machines
designed as portable saws.
(3) Flanges. Grinding machines shall be equipped with flanges in accordance
with paragraph (c) of this section.
(4) Work rests. On offhand grinding machines, work rests shall be used to
support the work. They shall be of rigid construction and designed to be
adjustable to compensate for wheel wear. Work rests shall be kept
adjusted closely to the wheel with a maximum opening of one-eighth inch
to prevent the work from being jammed between the wheel and the rest,
which may cause wheel breakage. The work rest shall be securely clamped
after each adjustment. The adjustment shall not be made with the wheel
in motion.
(5) Excluded machinery. Natural sandstone wheels and metal, wooden, cloth,
or paper discs, having a layer of abrasive on the surface are not
covered by this section.
(b) Guarding of abrasive wheel machinery-
(1) Cup wheels. Cup wheels (Types 6 and 11) shall be protected by:
(i) Safety guards as specified in paragraphs (b) (1) through (10) of this
section;
(ii) Band type guards as specified in paragraph (b) (11) of this section;
and
(iii) Special "Revolving Cup Guards" which mount behind the wheel and turn
with it. They shall be made of steel or other material with adequate
strength and shall enclose the wheel sides upward from the back for
one-third of the wheel thickness. The mounting features shall conform
with all requirements of this section. It is necessary to maintain
clearance between the wheel side and the guard. This clearance shall
not exceed one-sixteenth inch.
(2) Guard exposure angles. The maximum exposure angles specified in
paragraphs (b) (3) through (8) of this section shall not be exceeded.
Visors or other accessory equipment shall not be included as a part of
the guard when measuring the guard opening, unless such equipment has
strength equal to that of the guard.
(3) Bench and floor stands. The angular exposure of the grinding wheel
periphery and sides for safety guards used on machines known as bench
and floor stands should not exceed 90° or one-fourth of the periphery.
This exposure shall begin at a point not more than 65° above the
horizontal plane of the wheel spindle. (See Figures O-6 and O-7 and
paragraph (b)(9) of this section.)
{Figure No. O-6 Figure No. O-7}
Wherever the nature of the work requires contact with the wheel below
the horizontal plane of the spindle, the exposure shall not exceed 125°.
(See Figures O-8 and O-9.)
{Figure No. O-8 Figure No. O-9 }
(4) Cylindrical grinders. The maximum angular exposure of the grinding wheel
periphery and sides for safety guards used on cylindrical grinding
machines shall not exceed 180°. This exposure shall begin at a point not
more than 65° above the horizontal plane of the wheel spindle. (See
Figures O-10 and O-11 and subparagraph (9) of this paragraph.)
{Figure No. O-10 Figure No. O-11}
(5) Surface grinders and cutting-off machines. The maximum angular exposure
of the grinding wheel periphery and sides for safety guards used on
cutting-off machines and on surface grinding machines which employ the
wheel periphery shall not exceed 150°. This exposure shall begin at a
point not less than 15° below the horizontal plane of the wheel spindle.
(See Figures O-12 and O-13)
{Figure No. O-12 Figure No. O-13}
(6) Swing frame grinders. The maximum angular exposure of the grinding wheel
periphery and sides for safety guards used on machines known as swing
frame grinding machines shall not exceed 180°, and the top half of the
wheel shall be enclosed at all times. (See Figures O-14 and O-15.)
{Figure No. O-14 Figure No. O-15}
(7) Automatic snagging machines. The maximum angular exposure of the
grinding wheel periphery and sides for safety guards used on grinders
known as automatic snagging machines shall not exceed 180° and the top
half of the wheel shall be enclosed at all times. (See Figures O-14 and
O-15.)
(8) Top grinding. Where the work is applied to the wheel above the
horizontal centerline, the exposure of the grinding wheel periphery
shall be as small as possible and shall not exceed 60°. (See Figures
O-16 and O-17.)
{Figure No. O-16 Figure No. O-17}
(9) Exposure adjustment. Safety guards of the types described in
subparagraphs (3) and (4) of this paragraph, where the operator stands
in front of the opening, shall be constructed so that the peripheral
protecting member can be adjusted to the constantly decreasing diameter
of the wheel. The maximum angular exposure above the horizontal plane of
the wheel spindle as specified in paragraphs (b) (3) and (4) of this
section shall never be exceeded, and the distance between the wheel
periphery and the adjustable tongue or the end of the peripheral member
at the top shall never exceed one-fourth inch. (See Figures O-18, O-19,
O-20, O-21, O-22, and O-23.)
(10) Material requirements and minimum dimensions.
(i) See Figures O-36 and O-37 and Table O-9 for minimum basic thickness of
peripheral and side members for various types of safety guards and
classes of service.
(ii) If operating speed does not exceed 8,000 surface feet per minute cast
iron safety guards, malleable iron guards or other guards as described
in paragraph (b)(10)(iii) of this section shall be used.
(iii) Cast steel, or structural steel, safety guards as specified in
Figures O-36 and O-37 and Table O-9 shall be used where operating
speeds of wheels are faster than 8,000 surface feet per minute up to a
maximum of 16,000 surface feet per minute.
(iv) For cutting-off wheels 16 inches diameter and smaller and where speed
does not exceed 16,000 surface feet per minute, cast iron or malleable
iron safety guards as specified in Figures O-36 and O-37, and in Table
O-9 shall be used.
{Figure No. O-18 Figure No. O-19}
correct
Showing adjustable tongue giving required angular protection for all
sizes of wheel used.
{Figure No. O-20 Figure No. O-21}
correct
Showing movable guard with opening small enough to give required
protection for smallest size wheel used.
{Figure No. O-22 Figure No. O-23}
incorrect
Showing movable guard with size of opening correct for full size wheel
but too large for smaller wheels.
(v) For cutting-off wheels larger than 16 inches diameter and where speed
does not exceed 14,200 surface feet per minute, safety guards as
specified in Figures O-27 and O-28, and in Table O-1 shall be used.
(vi) For thread grinding wheels not exceeding 1 inch in thickness cast
iron or malleable iron safety guards as specified in Figures O-36 and
O-37, and in Table O-9 shall be used.
(11) Band type guards-general specifications. Band type guards shall conform
to the following general specifications:
(i) The bands shall be of steel plate or other material of equal or
greater strength. They shall be continuous, the ends being either
riveted, bolted, or welded together in such a manner as to leave the
inside free from projections.
(ii) The inside diameter of the band shall not be more than 1 inch larger
than the outside diameter of the wheel, and shall be mounted as nearly
concentric with the wheel as practicable.
(iii) The band shall be of sufficient width and its position kept so
adjusted that at no time will the wheel protrude beyond the edge of
the band a distance greater than that indicated in Figure O-29 and in
Table O-2 or the wall thickness (W), whichever is smaller.
(12) Guard design specifications. Abrasive wheel machinery guards shall meet
the design specifications of the American National Standard Safety Code
for the Use, Care, and Protection of Abrasive Wheels, ANSI B7.1-1970.
This requirement shall not apply to natural sandstone wheels or metal,
wooden, cloth, or paper discs, having a layer of abrasive on the
surface.
(c) Flanges-
(1) General requirements. All abrasive wheels shall be mounted between
flanges which shall not be less than one-third the diameter of the
wheel.
(i) Exceptions:
(a) Mounted wheels.
(b) Portable wheels with threaded inserts or projecting studs.
(c) Abrasive discs (inserted nut, inserted washer and projecting stud
type).
(d) Plate mounted wheels.
(e) Cylinders, cup, or segmental wheels that are mounted in chucks.
(f) Types 27 and 28 wheels.
(g) Certain internal wheels.
(h) Modified types 6 and 11 wheels (terrazzo).
(i) Cutting-off wheels, Types 1 and 27A (see paragraphs (c)(1) (ii) and
(iii) of this section).
(ii) Type 1 cutting-off wheels are to be mounted between properly relieved
flanges which have matching bearing surfaces. Such flanges shall be at
least one-fourth the wheel diameter.
(iii) Type 27A cutting-off wheels are designed to be mounted by means of
flat, not relieved, flanges having matching bearing surfaces and which
may be less than one-third but shall not be less than one-fourth the
wheel diameter. (See Figure O-24 for one such type of mounting.)
(iv) There are three general types of flanges:
(a) Straight relieved flanges (see Figure O-32);
(b) Straight unrelieved flanges (see Figure O-30);
(c) Adaptor flanges (see Figures O-33 and O-34);
(v) Regardless of flange type used, the wheel shall always be guarded.
Blotters shall be used in accordance with paragraph (c)(6) of this
section.
{Figure No. O-24}
The Type 27 A Wheel is mounted between flat non-relieved flanges of
equal bearing surfaces.
(2) [Reserved]
(3) Finish and balance. Flanges shall be dimensionally accurate and in good
balance. There shall be no rough surfaces or sharp edges.
(4) Uniformity of diameter.
(i) Both flanges, of any type, between which a wheel is mounted, shall be
of the same diameter and have equal bearing surface. Exceptions are
set forth in the remaining subdivisions of this subparagraph.
(ii) Type 27 and Type 28 wheels, because of their shape and usage, require
specially designed adaptors. The back flange shall extend beyond the
central hub or raised portion and contact the wheel to counteract the
side pressure on the wheel in use. The adaptor nut which is less than
the minimum one-third diameter of wheel fits in the depressed side of
wheel to prevent interference in side grinding and serves to drive the
wheel by its clamping force against the depressed portion of the back
flange. The variance in flange diameters, the adaptor nut being less
than one-third wheel diameter, and the use of side pressure in wheel
operation limits the use to reinforced organic bonded wheels. Mounts
which are affixed to the wheel by the manufacturer shall not be
reused. Type 27 and Type 28 wheels shall be used only with a safety
guard located between wheel and operator during use. (See Figure
O-24-A.)
{Figure No. O-24-A}
Types 27 and 28 wheels, because of their s
hape, require specially designed adaptors.
(iii) Modified Types 6 and 11 wheels (terrazzo) with tapered K dimension.
(5) Recess and undercut.
(i) Straight relieved flanges made according to Table O-6 and Figure O-32
shall be recessed at least one-sixteenth inch on the side next to the
wheel for a distance as specified in Table O-6.
(ii) Straight flanges of the adaptor or sleeve type (Table O-7 and Figures
O-33 and O-34) shall be undercut so that there will be no bearing on
the sides of the wheel within one-eighth inch of the arbor hole.
(6) Blotters.
(i) Blotters (compressible washers) shall always be used between flanges
and abrasive wheel surfaces to insure uniform distribution of flange
pressure. (See paragraph (d)(5) of this section.)
(ii) Exception:
(a) Mounted wheels.
(b) Abrasive discs (inserted nut, inserted washer, and projecting stud
type).
(c) Plate mounted wheels.
(d) Cylinders, cups, or segmental wheels that are mounted in chucks.
(e) Types 27 and 28 wheels.
(f) Certain Type 1 and Type 27A cutting-off wheels.
(g) Certain internal wheels.
(h) Type 4 tapered wheels.
(i) Diamond wheels, except certain vitrified diamond wheels.
(j) Modified Types 6 and 11 wheel (terrazzo)-blotters applied flat side
of wheel only.
(7) Driving flange. The driving flange shall be securely fastened to the
spindle and the bearing surface shall run true. When more than one wheel
is mounted between a single set of flanges, wheels may be cemented
together or separated by specially designed spacers. Spacers shall be
equal in diameter to the mounting flanges and have equal bearing
surfaces. (See paragraph (d)(6) of this section.)
(8) Dimensions.
(i) Tables O-4 and O-6 and Figures O-30 and O-32 show minimum dimensions
for straight relieved and unrelieved flanges for use with wheels with
small holes that fit directly on the machine spindle. Dimensions of
such flanges shall never be less than indicated.
(ii) Table O-5, and Table O-7 and Figures O-31, O-33, O-34 show minimum
dimensions for straight adaptor flanges for use with wheels having
holes larger than the spindle. Dimensions of such adaptor flanges
shall never be less than indicated.
(iii) Table O-8 and Figure O-35 show minimum dimensions for straight
flanges that are an integral part of wheel sleeves which are
frequently used on precision grinding machines. Dimensions of such
flanges shall never be less than indicated.
(9) Repairs and maintenance. All flanges shall be maintained in good
condition. When the bearing surfaces become worn, warped, sprung, or
damaged they should be trued or refaced. When refacing or truing, care
shall be exercised to make sure that proper relief and rigidity is
maintained as specified in paragraphs (c) (2) and (5) of this section
and they shall be replaced when they do not conform to these
subparagraphs and Table O-4, Figure O-30, Table O-5, Figure O-31, Table
O-6, Figure O-32, and Table O-8, Figure O-35. Failure to observe these
rules might cause excessive flange pressure around the hole of the
wheel. This is especially true of wheel-sleeve or adaptor flanges.
(d) Mounting-
(1) Inspection. Immediately before mounting, all wheels shall be closely
inspected and sounded by the user (ring test) to make sure they have not
been damaged in transit, storage, or otherwise. The spindle speed of the
machine shall be checked before mounting of the wheel to be certain that
it does not exceed the maximum operating speed marked on the wheel.
Wheels should be tapped gently with a light nonmetallic implement, such
as the handle of a screwdriver for light wheels, or a wooden mallet for
heavier wheels. If they sound cracked (dead), they shall not be used.
This is known as the "Ring Test".
(i) Wheels must be dry and free from sawdust when applying the ring test,
otherwise the sound will be deadened. It should also be noted that
organic bonded wheels do not emit the same clear metallic ring as do
vitrified and silicate wheels.
{Figure No. O-25 Figure No. O-26}
(ii) "Tap" wheels about 45° each side of the vertical centerline and about
1 or 2 inches from the periphery as indicated by the spots in Figure
O-25 and Figure O-26. Then rotate the wheel 45° and repeat the test. A
sound and undamaged wheel will give a clear metallic tone. If cracked,
there will be a dead sound and not a clear "ring."
(2) Arbor size. Grinding wheels shall fit freely on the spindle and remain
free under all grinding conditions. A controlled clearance between the
wheel hole and the machine spindle (or wheel sleeves or adaptors) is
essential to avoid excessive pressure from mounting and spindle
expansion. To accomplish this, the machine spindle shall be made to
nominal (standard) size plus zero minus .002 inch, and the wheel hole
shall be made suitably oversize to assure safety clearance under the
conditions of operating heat and pressure.
(3) Surface condition. All contact surfaces of wheels, blotters and flanges
shall be flat and free of foreign matter.
(4) Bushing. When a bushing is used in the wheel hole it shall not exceed
the width of the wheel and shall not contact the flanges.
(5) Blotters. When blotters or flange facings of compressible material are
required, they shall cover entire contact area of wheel flanges.
Blotters need not be used with the following types of wheels:
(i) Mounted wheels.
(ii) Abrasive discs (inserted nut, inserted washer, and projecting-stud
type).
(iii) Plate mounted wheels.
(iv) Cylinders, cups, or segmental wheels that are mounted in chucks.
(v) Types 27 and 28 wheels.
(vi) Certain Type 1 and Type 27A cutting-off wheels.
(vii) Certain internal wheels.
(viii) Type 4 tapered wheels.
(ix) Diamond wheels, except certain vitrified diamond wheels.
(6) Multiple wheel mounting. When more than one wheel is mounted between a
single set of flanges, wheels may be cemented together or separated by
specially designed spacers. Spacers shall be equal in diameter to the
mounting flanges and have equal bearing surfaces. When mounting wheels
which have not been cemented together, or ones which do not utilize
separating spacers, care must be exercised to use wheels specially
manufactured for that purpose.
Table O-1-Minimum Basic Thickness for Peripheral and Side Members for Safety
Guards Used With Cutting-Off Wheels
┌──────────┬─────────┬───────┬─────────────────────────────────────────────────┐
│ │ │ │ Cutting off wheel diameters │
│ Material │ Maximum │ ├─────────┬─────────┬─────────┬─────────┬─────────┤
│ used in │thickness│ Speed │ 6 to 11 │ Over 11 │ Over 20 │ Over 30 │ Over 48 │
│construc- │ of │not to │ inches │ to 20 │ to 30 │ to 48 │ to 72 │
│ tion of │ cutting │exceed │ │ inches │ inches │ inches │ inches │
│ guard │off wheel│ ├────┬────┼────┬────┼────┬────┼────┬────┼────┬────┤
│ │ │ │ A │ B │ A │ B │ A │ B │ A │ B │ A │ B │
├──────────┼─────────┼───────┼────┼────┼────┼────┼────┼────┼────┼────┼────┼────┤
│Structural│1/2 inch │14,200 │1/16│1/16│3/32│3/32│ 1/8│ 1/8│3/16│3/16│ 1/4│ 1/4│
│ steel │ or less│ SFPM.│ │ │ │ │ │ │ │ │ │ │
│ (min. │ │ │ │ │ │ │ │ │ │ │ │ │
│ tensile │ │ │ │ │ │ │ │ │ │ │ │ │
│ strength│ │ │ │ │ │ │ │ │ │ │ │ │
│ 60,000 │ │ │ │ │ │ │ │ │ │ │ │ │
│ p.s.i.).│ │ │ │ │ │ │ │ │ │ │ │ │
│ │1/2 inch │16,000 │3/32│ 1/8│ 1/8│ 1/8│3/16│ 1/8│ 1/4│3/16│5/16│ 1/4│
│ │ or less│ SFPM.│ │ │ │ │ │ │ │ │ │ │
└──────────┴─────────┴───────┴────┴────┴────┴────┴────┴────┴────┴────┴────┴────┘
Table O-3-Guide for Construction of Band Type Guards
[Maximum Wheel Speed 7,000 SFPM]
┌───────────────┬──────────────────────────────────┬─────────┬────────┬────────┐
│ │ │ │ │Maximum │
│ Minimum │ │ Minimum │ Minimum│distance│
│ material │ Diameter of wheel │thickness│diameter│between │
│specifications │ │of band A│ of │centers │
│ │ │ │ rivets │ of │
│ │ │ │ │ rivets │
├───────────────┴──────────────────────────────────┴─────────┴────────┴────────┤
│ Inches │
├───────────────┬──────────────────────────────────┬─────────┬────────┬────────┤
│Hot rolled │Under 8...........................│ 1/16│ 3/16│ 3/4│
│ steel SAE │ │ │ │ │
│ 1008.........│ │ │ │ │
│ │8 to 24...........................│ 1/8│ 1/4│ 1│
│ │Over 24 to 30.....................│ 1/4│ 3/8│ 1 1/4│
└───────────────┴──────────────────────────────────┴─────────┴────────┴────────┘
Table O-5-Minimum Dimensions for Straight Adaptor Flange-for Organic Bonded
Wheels Over 1 1/4 Inches Thick^1
[In inches]
┌────────────────────────────┬────────┬────────┬─────────┬─────────┬─────────┐
│ │ │ │ │E-Minimum│ │
│ │ Wheel │ B- │D-Minimun│thickness│F^1-(D-E)│
│ Wheel diameter │ hole │Minimum │thickness│of flange│ minimum │
│ │diameter│ flange │of flange│ at edge │thickness│
│ │ │diameter│ at bore │ of │ │
│ │ │ │ │undercut │ │
├────────────────────────────┼────────┼────────┼─────────┼─────────┼─────────┤
│12 to 14....................│ 4│ 6│ 7/8│ 3/8│ 1/2│
│ │ 5│ 7│ 7/8│ 3/8│ 1/2│
│ │ 6│ 8│ 7/8│ 3/8│ 1/2│
│Larger than 14 to 18........│ 4│ 6│ 7/8│ 3/8│ 1/2│
│ │ 5│ 7│ 7/8│ 3/8│ 1/2│
│ │ 6│ 8│ 7/8│ 3/8│ 1/2│
│ │ 7│ 9│ 7/8│ 3/8│ 1/2│
│ │ 8│ 10│ 7/8│ 3/8│ 1/2│
│Larger than 18 to 24........│ 6│ 8│ 1│ 1/2│ 1/2│
│ │ 7│ 9│ 1│ 1/2│ 1/2│
│ │ 8│ 10│ 1│ 1/2│ 1/2│
│ │ 10│ 12│ 1│ 1/2│ 1/2│
│ │ 12│ 14│ 1│ 1/2│ 1/2│
│Larger than 24 to 30........│ 12│ 15│ 1│ 1/2│ 1/2│
│Larger than 30 to 36........│ 12│ 15│ 1 3/8│ 7/8│ 1/2│
└────────────────────────────┴────────┴────────┴─────────┴─────────┴─────────┘
^1. For wheels under 1 1/4 inches thick F dimension shall not exceed 40
percent of wheel thickness.
Table O-6-Minimum Dimensions for Straight Relieved Flanges^1
[In inches]
┌───────────────────────────┬────────┬─────────────────┬─────────┬─────────┐
│ │ B- │ │ │E-Minimum│
│ │Minimum │C-Radial width of│D-Minimum│thickness│
│ A-Diameter of wheel │outside │ bearing surface │thickness│of flange│
│ │diameter│ │of flange│ at edge │
│ │ of ├────────┬────────┤ at bore │of recess│
│ │flanges │Minimum │Maximum │ │ │
├───────────────────────────┼────────┼────────┼────────┼─────────┼─────────┤
│1..........................│ 3/8│ 1/16│ 1/8│ 1/16│ 1/16│
│2..........................│ 3/4│ 1/8│ 3/16│ 1/8│ 3/32│
│3..........................│ 1│ 1/8│ 3/16│ 3/16│ 3/32│
│4..........................│ 1 3/8│ 1/8│ 3/16│ 3/16│ 1/8│
│5..........................│ 1 3/4│ 3/16│ 1/4│ 1/4│ 1/8│
│6..........................│ 2│ 1/4│ 1/2│ 3/8│ 3/16│
│7..........................│ 2 1/2│ 1/4│ 1/2│ 3/8│ 3/16│
│8..........................│ 3│ 1/4│ 1/2│ 3/8│ 3/16│
│10.........................│ 3 1/2│ 5/16│ 5/8│ 3/8│ 1/4│
│12.........................│ 4│ 5/16│ 5/8│ 1/2│ 5/16│
│14.........................│ 4 1/2│ 3/8│ 3/4│ 1/2│ 5/16│
│16.........................│ 5 1/2│ 1/2│ 1│ 1/2│ 5/16│
│18.........................│ 6│ 1/2│ 1│ 5/8│ 3/8│
│20.........................│ 7│ 5/8│ 1 1/4│ 5/8│ 3/8│
│22.........................│ 7 1/2│ 5/8│ 1 1/4│ 5/8│ 7/16│
│24.........................│ 8│ 3/4│ 1 1/4│ 5/8│ 7/16│
│26.........................│ 8 1/2│ 3/4│ 1 1/4│ 5/8│ 1/2│
│28.........................│ 10│ 7/8│ 1 1/2│ 3/4│ 1/2│
│30.........................│ 10│ 7/8│ 1 1/2│ 3/4│ 5/8│
│36.........................│ 12│ 1│ 2│ 7/8│ 3/4│
│42.........................│ 14│ 1│ 2│ 7/8│ 3/4│
│48.........................│ 16│ 1 1/4│ 2│ 1 1/8│ 1│
│60.........................│ 20│ 1 1/4│ 2│ 1 1/4│ 1 1/8│
│72.........................│ 24│ 1 1/2│ 2 1/2│ 1 3/8│ 1 1/4│
└───────────────────────────┴────────┴────────┴────────┴─────────┴─────────┘
^1. Flanges for wheels under 2 inches diameter may be unrelieved and
shall be maintained flat and true.
Table O-7-Minimum Dimensions for Straight Flanges-for Mechanical Grinders
12,500 S.F.P.M. to 16,5 S.F.P.M.^1
┌────────────┬────────────┬────────────┬────────────┬────────────┬────────────┐
│ │ │ │ D-Minimum │ E-Minimum │ │
│ Wheel │ Wheel hole │ B-Minimum │thickness of│thickness of│ F^2-(D-E) │
│ diameter │ diameter │ flange │ flange at │ flange at │ minimum │
│ │ │ diameter │ bore │ edge of │ thickness │
│ │ │ │ │ undercut │ │
├────────────┼────────────┼────────────┼────────────┼────────────┼────────────┤
│ 20│ 6│ 8│ 1│ 1/2│ 1/2│
│ 20│ 8│ 10│ 1 1/2│ 3/4│ 3/4│
│ 24│ 12│ 15│ 2│ 1│ 1│
│ 30│ 12│ 15│ 2│ 1│ 1│
│ 36│ 12│ 15│ 2│ 1│ │
└────────────┴────────────┴────────────┴────────────┴────────────┴────────────┘
^1. Flanges shall be of steel, quality SAE 1040 or equivalent, annealed
plate, heat treated to R. 25-30.
^2. For wheels under 1 1/4 inch thick F dimension shall not exceed 40
percent of wheel thickness.
Table O-8-Minimum Dimensions for Straight Flanges Used as Wheel Sleeves for
Precision Grinding Only
[In inches]
┌───────────────────────────────────────┬────────┬────────┬─────────┬─────────┐
│ │ │ B- │ │E-Minimum│
│ │ Wheel │Minimum │D-Minimum│thickness│
│ Wheel diameter │ hole │outside │thickness│of flange│
│ │diameter│diameter│of flange│ at edge │
│ │ │ of │ at bore │ of │
│ │ │ flange │ │undercut │
├───────────────────────────────────────┼────────┼────────┼─────────┼─────────┤
│12 to 14...............................│ 5│ 7│ 1/2│ 7/16│
│Larger than 14 to 20...................│ 5│ 7│ 5/8│ 7/16│
│ │ 6│ 8│ 5/8│ 7/16│
│ │ 8│ 10│ 5/8│ 7/16│
│ │ 10│ 11 1/2│ 5/8│ 7/16│
│ │ 12│ 13 1/2│ 5/8│ 7/16│
│Larger than 20 to 30...................│ 8│ 10│ 3/4│ 1/2│
│ │ 10│ 11 1/2│ 3/4│ 1/2│
│ │ 12│ 13 1/2│ 3/4│ 1/2│
│ │ 16│ 17 1/2│ 3/4│ 1/2│
│Larger than 30 to 42...................│ 12│ 13 1/2│ 3/4│ 1/2│
│ │ 16│ 17 1/2│ 3/4│ 1/2│
│ │ 18│ 19 1/2│ 3/4│ 1/2│
│ │ 20│ 21 1/2│ 3/4│ 1/2│
│Larger than 42 to 60...................│ 16│ 20│ 1│ 3/4│
│ │ 20│ 24│ 1│ 3/4│
│ │ 24│ 29│ 1 1/8│ 7/8│
└───────────────────────────────────────┴────────┴────────┴─────────┴─────────┘
Note: These flanges may be clamped together by means of a central nut, or
by a series of bolts or some other equivalent means of fastening. For hole
sizes smaller than shown in this table, use table 12.
Table O-9(a)-Minimum Basic Thicknesses of Peripheral and Side Members for
Safety Guards
[In inches]
┌────────────────────┬─────────┬───────────────────────────────────────────────┐
│ │ Maximum │ Grinding wheel diameters │
│ Material used in │thickness├───────────┬───────────┬───────────┬───────────┤
│ construction of │ of │ 3 to 6 │ Over 6 to │Over 12 to │Over 16 to │
│ guard │grinding │ inches │ 12 inches │ 16 inches │ 20 inches │
│ │ wheel ├─────┬─────┼─────┬─────┼─────┬─────┼─────┬─────┤
│ │ │ A │ B │ A │ B │ A │ B │ A │ B │
├────────────────────┼─────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
│Material │ 2│ 1/4│ 1/4│ 3/8│ 5/16│ 1/2│ 3/8│ 5/8│ 1/2│
│satis- │ 4│ 5/16│ 5/16│ 3/8│ 5/16│ 1/2│ 3/8│ 3/4│ 5/8│
│factory^1 │ 6│ 3/8│ 5/16│ 1/2│ 7/16│ 5/8│ 1/2│ 1│ 5/8│
│for │ 8│ │ │ 5/8│ 9/16│ 7/8│ 3/4│ 1│ 3/4│
│speeds │ 10│ │ │ 3/4│11/16│ 7/8│ 3/4│ 1│ 3/4│
│up to │ 16│ │ │ │ │1 1/8│ 1│1 1/4│ 1│
│8,000 │ 20│ │ │ │ │ │ │1 3/8│1 1/8│
│SFPM. │ │ │ │ │ │ │ │ │ │
│Cast iron (min. │ │ │ │ │ │ │ │ │ │
│ tensile strength │ │ │ │ │ │ │ │ │ │
│ 20,000 p.s.i.) │ │ │ │ │ │ │ │ │ │
│ Class 20. │ │ │ │ │ │ │ │ │ │
├────────────────────┼─────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
│Material │ 2│ 1/4│ 1/4│ 3/8│ 5/16│ 1/2│ 3/8│ 5/8│ 1/2│
│satis- │ 4│ 5/16│ 5/16│ 3/8│ 5/16│ 1/2│ 3/8│ 5/8│ 1/2│
│factory ^1 │ 6│ 3/8│ 5/16│ 1/2│ 7/16│ 5/8│ 1/2│ 3/4│ 5/8│
│for │ 8│ │ │ 1/2│ 7/16│ 5/8│ 1/2│ 3/4│ 5/8│
│speeds │ 10│ │ │ 1/2│ 7/16│ 5/8│ 1/2│ 3/4│ 5/8│
│up to │ 16│ │ │ │ │13/16│11/16│13/16│11/16│
│9,000 │ 20│ │ │ │ │ │ │ 7/8│ 3/4│
│SFPM. │ │ │ │ │ │ │ │ │ │
│Malleable iron (min.│ │ │ │ │ │ │ │ │ │
│ tensile strength │ │ │ │ │ │ │ │ │ │
│ 50,000 p.s.i.) │ │ │ │ │ │ │ │ │ │
│ Grade 32510. │ │ │ │ │ │ │ │ │ │
│Materials │ 2│ 1/4│ 1/4│ 5/16│ 5/16│ 3/8│ 3/8│ 1/2│ 7/16│
│satis- │ 4│ 1/4│ 1/4│ 1/2│ 1/2│ 1/2│ 1/2│ 9/16│ 1/2│
│factory^1 │ 6│ 3/8│ 1/4│ 3/4│ 5/8│ 3/4│ 5/8│ 3/4│ 5/8│
│for │ 8│ │ │ 7/8│ 3/4│ 7/8│ 3/4│ 7/8│ 3/4│
│speeds │ 10│ │ │ 1│ 7/8│ 1│ 7/8│ 1│ 7/8│
│up to │ 16│ │ │ │ │1 1/4│1 1/8│1 1/4│1 1/8│
│16,000 │ 20│ │ │ │ │ │ │1 3/8│1 1/4│
│SFPM. │ │ │ │ │ │ │ │ │ │
│Steel castings (min.│ │ │ │ │ │ │ │ │ │
│ tensile strength │ │ │ │ │ │ │ │ │ │
│ 60,000 p.s.i.) │ │ │ │ │ │ │ │ │ │
│ Grade V60-30. │ │ │ │ │ │ │ │ │ │
├────────────────────┼─────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
│Structural │ 2│ 1/8│ 1/16│ 5/16│ 1/4│ 5/16│ 1/4│ 5/16│ 1/4│
│steel │ 4│ 1/8│ 1/16│ 3/8│ 5/16│ 3/8│ 5/16│ 3/8│ 5/16│
│(min. │ 6│ 3/16│ 1/16│ 1/2│ 3/8│ 7/16│ 3/8│ 7/16│ 3/8│
│tensile │ 8│ │ │ 1/2│ 3/8│ 9/16│ 7/16│ 9/16│ 7/16│
│strength │ 10│ 9/16│ 7/16│ 5/8│ 1/2│ 5/8│ 1/2│ 5/8│ 1/2│
│60,000 │ 16│ │ │ │ │ 5/8│ 9/16│ 3/4│ 5/8│
│p.s.i.) │ 20│ │ │ │ │ │ │13/16│11/16│
└────────────────────┴─────────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┘
^1. The recommendations listed in the above table are guides for the
conditions stated. Other material, designs or dimensions affording equal or
superior protection are also acceptable.
Table O-9(b)-Minimum Basic Thicknesses of Peripheral and Side Members for
Safety Guards
[In inches]
┌────────────────────┬─────────┬───────────────────────────────────────────────┐
│ │ Maximum │ Grinding wheel diameters │
│ Material used in │thickness├───────────────┬───────────────┬───────────────┤
│ construction of │ of │ Over 20 to 24 │ Over 24 to 30 │ Over 30 to 48 │
│ guard │grinding │ inches │ inches │ inches │
│ │ wheel ├───────┬───────┼───────┬───────┼───────┬───────┤
│ │ │ A │ B │ A │ B │ A │ B │
├────────────────────┼─────────┼───────┼───────┼───────┼───────┼───────┼───────┤
│Material │ 2│ 7/8│ 5/8│ 1│ 3/4│ 1 1/4│ 1│
│satis- │ 4│ 1│ 5/8│ 1 1/8│ 3/4│ 1 3/8│ 1│
│factory^1 │ 6│ 1 1/8│ 3/4│ 1 1/4│ 7/8│ 1 1/2│ 1 1/8│
│for │ 8│ 1 1/8│ 3/4│ 1 1/4│ 7/8│ 1 1/2│ 1 1/8│
│speeds │ 10│ 1 1/8│ 3/4│ 1 1/4│ 7/8│ 1 1/2│ 1 1/8│
│up to │ 16│ 1 5/16│ 1│ 1 7/16│ 1 1/16│ 1 3/4│ 1 3/8│
│8,000 │ 20│ 1 3/8│ 1 1/8│ 1 1/2│ 1 3/8│ 2│ 1 5/8│
│SFPM. │ │ │ │ │ │ │ │
│Cast iron (min. │ │ │ │ │ │ │ │
│ tensile strength │ │ │ │ │ │ │ │
│ 20,000 p.s.i.) │ │ │ │ │ │ │ │
│ Class 20. │ │ │ │ │ │ │ │
├────────────────────┼─────────┼───────┼───────┼───────┼───────┼───────┼───────┤
│Material │ 2│ 3/4│ 5/8│ 7/8│ 3/4│ 1│ 7/8│
│satis- │ 4│ 3/4│ 5/8│ 7/8│ 3/4│ 1 1/8│ 7/8│
│factory^1 │ 6│ 7/8│ 5/8│ 1│ 3/4│ 1 1/4│ 7/8│
│for │ 8│ 7/8│ 5/8│ 1│ 3/4│ 1 1/4│ 7/8│
│speeds │ 10│ 7/8│ 5/8│ 1│ 3/4│ 1 1/4│ 7/8│
│up to │ 16│ 1│ 3/4│ 1 1/8│ 7/8│ 1 3/8│ 1│
│9,000 │ 20│ 1│ 3/4│ 1 1/8│ 7/8│ 1 1/2│ 1 1/8│
│SFPM. │ │ │ │ │ │ │ │
│Malleable iron (min.│ │ │ │ │ │ │ │
│ tensile strength │ │ │ │ │ │ │ │
│ 50,000 p.s.i.) │ │ │ │ │ │ │ │
│ Grade 32510. │ │ │ │ │ │ │ │
│Materials │ 2│ 5/8│ 1/2│ 3/4│ 5/8│ 7/8│ 3/4│
│satis- │ 4│ 5/8│ 1/2│ 3/4│ 5/8│ 1│ 3/4│
│factory^1 │ 6│ 13/16│ 11/16│ 13/16│ 11/16│ 1 1/8│ 3/4│
│for │ 8│ 7/8│ 3/4│ 15/16│ 13/16│ 1 3/8│ 1│
│speeds │ 10│ 1 1/8│ 15/16│ 1 1/8│ 1│ 1 7/16│ 1 1/16│
│up to │ 16│ 1 1/4│ 1 1/8│ 1 1/4│ 1 1/8│1 13/16│ 1 7/16│
│16,000 │ 20│ 1 3/8│ 1 1/4│ 1 7/16│ 1 5/16│ 2 1/16│1 11/16│
│SFPM. │ │ │ │ │ │ │ │
│Steel castings (min.│ │ │ │ │ │ │ │
│ tensile strength │ │ │ │ │ │ │ │
│ 60,000 p.s.i.) │ │ │ │ │ │ │ │
│ Grade V60-30. │ │ │ │ │ │ │ │
├────────────────────┼─────────┼───────┼───────┼───────┼───────┼───────┼───────┤
│Structural │ 2│ 5/16│ 1/4│ 3/8│ 5/16│ 1/2│ 3/8│
│steel │ 4│ 3/8│ 5/16│ 3/8│ 5/16│ 1/2│ 3/8│
│(min. │ 6│ 7/16│ 3/8│ 7/16│ 3/8│ 3/4│ 1/2│
│tensile │ 8│ 9│ │ │ │ │ │
│strength │ 10│ 5/8│ 1/2│ 7/8│ 5/8│ │ │
│60,000 │ 16│ 3/4│ 5/8│ 13/16│ 11/16│ 1 1/16│ 13/16│
│p.s.i.) │ 20│ 13/16│ 11/16│ 7/8│ 3/4│ 1 3/16│ 15/16│
└────────────────────┴─────────┴───────┴───────┴───────┴───────┴───────┴───────┘
^1. The recommendations listed in the above table are guides for the
conditions stated. Other material, designs or dimensions affording equal or
superior protection are also acceptable.
Table O-2-Exposure Versus Wheel Thickness
[In inches]
┌──────────────────────────────────────────────────────────────────┬───────────┐
│ │ Maximum │
│ Overall thickness of wheel (T) │exposure of│
│ │ wheel (C) │
├──────────────────────────────────────────────────────────────────┼───────────┤
│1/2...............................................................│ 1/4│
│1.................................................................│ 1/2│
│2.................................................................│ 3/4│
│3.................................................................│ 1│
│4.................................................................│ 1 1/2│
│5 and over........................................................│ 2│
└──────────────────────────────────────────────────────────────────┴───────────┘
Table O-4-Minimum Dimensions for Straight Unrelieved Flanges for Wheels with
Threaded Inserts or Projecting Studs
┌─────────────────────────┬─────────────────────────┬─────────────────────────┐
│ A-Diameter of wheel │ B^1-Minimum outside │ T-Minimum thickness of │
│ │ diameter of flange │ flange │
├─────────────────────────┼─────────────────────────┼─────────────────────────┤
│ 1│ 5/8│ 1/8│
│ 2│ 1│ 1/8│
│ 3│ 1│ 3/16│
│ 4│ 1 3/8│ 3/16│
│ 5│ 1 3/4│ 1/4│
│ 6│ 2│ 3/8│
└─────────────────────────┴─────────────────────────┴─────────────────────────┘
^1. Note: Must be large enough to extend beyond the bushing. Where prong
anchor or cupback bushing are used, this footnote does not apply.
[39 FR 23502, June 27, 1974, as amended at 43 FR 49750, Oct. 24, 1978; 49 FR
5323, Feb. 10, 1984]
