Grainger Hex Head Cap Screw: Steel, Grade 5, Zinc Plated, 5/16"-18, Coarse, 3 1/2 in lg, Inch, 100 PK Product Details System of Measurement Inch Thread Size 5/16"-18 Material Steel Material Grade/Class Grade 5 Finish Zinc Plated Thread Type Coarse Thread Style Partially Threaded Minimum Thread Length 7/8 in Head Width 1/2 in Head Height 13/64 in Tensile Strength 105,000 psi Thread Direction Right Hand Hex Head Cap Screw Type Hex Head Cap Screw Head Style Hex Rockwell Hardness HRC19 Overall Length 3-1/2 in Drive Hex Thread Fit 2A Fastener Length 3-1/2 in Dimensional Standards ASME B18.2.1 Material Quality Standards SAE J429 Pack Size Small Pack UNSPSC 31161501 Country of Origin Varies (subject to change) Product Description Commonly used Grade 5 hex cap screws are heavier duty than Grade 2 steel options and are made from medium carbon steel and heat-treated. Grade 5 steel has 120,000 psi tensile strength and meets ASME B18.2.1 dimensional standards and SAE J429 material quality standards. These screws may be used in medium-duty applications. They come in a black oxide finish or may be zinc plated or chrome plated. Zinc plating helps provide durability in wet environments. Chrome plating increases the hardness, durability, and corrosion resistance of screws. 2077a bottom right