Hardness Scale for Various Materials

MATERIALBRINELL HARDNESSDrilled Diameter With Suggested Feed Rate Below
1/16″1/8″1/4″1/2″3/4″1″1-1/2″2″
Aluminum99-101.001.003.007.012.016.020.025.030
Aluminum Bronze170-187.001.003.004.008.010.012.015.020
Balkelite.002.005.006.008.010.012.015.015
Brass192-202.001.003.004.008.012.018.020.022
Bronze, Common166-183.001.003.004.008.012.018.020.022
Bronze Phos.; 1/2 Hard187-202.001.003.004.008.010.012.015.020
Bronze Phos.; Soft149-163.001.003.004.008.012.018.020.022
Celluloid.002.004.005.006.006.008.008.010
Copper80-85.001.003.004.008.010.012.015.020
Copper Mang.; 30% Mn134.001.003.005.007.009.012.014.016
Duralumin90-104.001.003.005.010.015.018.020.025
Iron, Cast; Med Soft196.001.003.005.008.010.012.014.015
Iron, Cast; Hard293-302.001.003.005.007.009.012.012
Iron, Cast; Chilled402.001.003.005.007.009.011.011
Iron, Malleable112-126.002.004.007.010.012.015.018
Monel149-170.002.003.006.008.010.012.015
Nickel, Pure187-202.002.003.006.008.015.018.020
Nickel, Steel; 3 1/2%196-241.002.003.006.008.010.012.015
Rubber, Hard.005.010.012.015.018.020.025.030
Screw Stock, C.R.170-196.001.003.004.007.010.012.015.018
Stl, Carbon175-225.001.003.004.007.010.012.015.018
Stl, Drop Forged170-196.001.002.004.007.010.012.015.018
Stl, Machinery170-196.001.003.005.009.012.013.018.022
Stl, Magnet; Soft241-302.002.003.006.008.009.010.011
Stl, Magnet; Hard321-512.0005.001.002.002.003.003.004
Stl, Mang.; 7-13%187-217.0005.001.002.002.003.003.004
Stl, Mild; .20-.30C170-202.001.003.005.010.015.018.020.025
Stl, Molybdenum196-235.002.004.006.010.012.015.018
Stl, Spring402.002.003.005.007.009.010.010
Stl, Stainless150-225.001.002.004.006.008.011.013.016
Stl, Stainless460-520.0005.001.002.002.003.003.004
Stl, .40-.50C170-196.001.002.004.007.010.012.015.018
Stl, Struct; A-36160.001.003.005.010.015.018.020.025
Stl, Tool; SAE, Forged149.002.003.006.009.011.014.016
Stl, Tool; SAE, Forged402.0005.001.002.002.003.003.004
Zinc, Alloy112-126.002.003.007.012.016.018.020.025

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