5/8-18 x 3 Alloy Steel Socket Head Cap Screw is commonly used where an Allen-style socket drive is preferred over external-wrench hardware in confined equipment layouts. The size callout supports bill-of-material consistency when production-floor assemblies cannot accept a substitute fastener. Selected for precision assemblies, manufacturing plants, and power transmission, it gives maintenance teams a searchable alloy steel socket screw callout. The socket head form provides a cylindrical head suited to counterbores and recessed mounting pockets. This keeps the listing focused on the fastener geometry rather than broad catalog language. Technical Highlights Material: Alloy Steel Thread: 5/8-18 Length: 3 in. Nominal Body Diameter: .625 in. Head Diameter: 0.921 in. min / 0.938 in. max Head Height: 0.616 in. min / 0.625 in. max Hex Key Size: 1/2 Drive Type: Internal hex socket Call 773-775-7900 or email Sales@coldheaders.com for pricing, availability, or a quote.