Tool Steel Rod, Material Tool Steel, Material Grade O1, Overall Length 36 in, Heat Treatable Heat Treatable, Heat Treatment Oil-Hardened, Mechanical Finish Precision Ground, Outside Diameter 3/8 in, Outside Diameter Tolerance +/-0.0005 in, Yield Strength 55,000 psi, Fabrication Hot Rolled, Rockwell Hardness 100 HRB, Brinell Hardness 241 BHN, Tensile Strength 95,000 psi, Machinability 90 Percent, Length Tolerance +0.125 in/0 in, Includes Material Certificate Material Test Report