Arbor Spacer Low Carbon Steel Full Hard Temper Thickness 0.005 In Thickness 0.127 mm Thickness Tolerance +/-0.0005 In Inside Dia 1 1/4 In ID Tolerance +0.011 In Outside Dia 1 3/4 In OD Tolerance +/-0.002 In Keyway Width 5/16 In Keyway Depth 1/8 In Tensile Strength 80 000 PSI Rockwell Hardness B90 Meets AISI 1008-1010 Package 10