Hex Head Cap Screws feature hexagon-shaped heads for socket or wrench tightening. - Grade 9 steel construction offers higher tensile strength and higher yield strength than Grade 8 steel. System of Measurement / Inch Cap Screw Type / Hex Tap Bolt Basic Material / Steel Material Grade / Grade 8 Fastener Finish / Zinc Yellow Dia./Thread Size / 3/8"-16 Fastener Length / 1 1/2 in Fastener Thread Direction / Right Hand Fastener Thread Type / UNC (Coarse) Fastener Thread Style / Partially Threaded Fastener Industry Standards / ASME B18.2.1 Head Type / Hex Head Height / 15/64 in Head Width / 0.5625 in Proof Load / 120,000 psi Tensile Strength / 150,000 psi Rockwell Hardness / C33 to C39