Nominal Speeds for Tapping Stainless Steels (a)

   Type of     Condition (b)         Brinell          Speed,
   steel                             hardness          sfm

   FM Fer       Ann                 135 to 185          50
   FM Mar       Ann                 135 to 185          50
                Ann or CD           185 to 240          40
                Q and T             275 to 325          30
                Q and T             375 to 425          10
   FM Aus       Ann                 135 to 185          40
                CD                  225 to 275          35
   Ferritic     Ann                 135 to 185          30
   Mar(410)     Ann                 135 to 185          35
                Ann                 175 to 225          30
                Q and T             275 to 325          20
                Q and T             375 to 425          10
   Mar(431)     Ann                 225 to 275          25
                Q and T             275 to 325          20
                Q and T             375 to 425          10
   Mar(440)     Ann                 225 to 275          20
                Q and T             275 to 325          15
                Q and T             375 to 425          10
                Q and T           Rc 48 to 52            5
   Aus(304)     Ann                 135 to 185          25
                CD                  225 to 275          20
   Aus(316)     Ann                 135 to 185          20


 (a) For tapping steels under 375 Bhn, M10, M7 and M1 high speed steel taps.
     For steels over 375 Bhn, M3 and M40 taps.
 (b) Ann = Annealed    CD = Cold drawn     Q and T = Quenched and tempered
     Hard = Hardened   N and T = Normalized and tempered