Shoulder Screw, Self-Locking, Alloy Steel, Plain Finish, Head Style Knurled, System of Measurement Inch, Thread Size 1/4-20, Hex Socket Drive Type, Drive Size 5/32 in, Shoulder Dia. 5/16 in, Shoulder Length 1/2 in, Thread Length 7/16 in, Head Dia. 7/16 in, Head Height 7/32 in, Shoulder Length Tolerance 0.005 in, Min. Tensile Strength (PSI) 140,000 psi, Shear Strength (PSI) 84,000 psi, Temp. Range (F) 250 Degrees , Class 3A, Rockwell Hardness C32 to 43, Meets/Exceeds ASME B18.3