Shoulder Screw Standard 18-8 Stainless Steel Head Style Socket Thread Size 5/16-18 Drive Type Hex Drive Size 3/16 In Shoulder Dia 0.371-0.373 In Shoulder Length 3 1/2 In Thread Length 1/2 In Head Dia 9/16 In Head Height 1/4 In Shoulder Length Tolerance 0.010 In Min In Tensile Strength 70 000 PSI Rockwell Hardness B55 Package 2