Item Specifications UPC 842176122403 Package Quantity 50 Size 5/16"-18 x 5/8" Head Style Button Head Diameter 0.547" Head Height 0.166" Drive Style Allen Hex Key Drive Size 3/16" Inch / Metric Inch Thread Size 5/16"-18 Thread Dia. 0.3125" Thread Class Class 3A Coarse / Fine Coarse Threads Per Inch (TPI) 18 Thread Coverage Full Thread Length 5/8" Thread Length Dec. 0.625" Material Alloy Steel Grade Grade 8 Finish Black Oxide Specification 1 ASME : B18.3 Specification 2 ASTM : F835 Tensile Strength 120,000 PSI Core Hardness Rockwell C37 Item Type Socket Screws Product Code 5150-4490 SKU 201135