Socket Head Cap Screw Head Type Flat Material Alloy Steel Black Oxide Finish Thread Size 18 Drive Type Hex Socket Drive Size 3/16 In. Thread Type Coarse Thread Style Fully Threaded Thread Direction Right Hand Length under Head 1-1/2 In. Thread Length 1-1/2 In. Head Height 5/16 In. Thread Dia 5/16 In. Head Dia 7/16 In. Temp Range -65 Degrees F to 300 Degrees F Rockwell Hardness HRC 39 to 44 Min Tensile Strength 145 000 psi Meets/Exceeds ASTM F835 ASME B18.3