5/8-18 x 9 Alloy Steel Socket Head Cap Screw gives engineers an internal-hex fastener for mechanical joints where socket engagement and dimensional consistency matter. This size keeps the specified 5/8-18 thread and 9 in. length visible for stockroom identification and purchasing review. Common uses include tooling, material handling, and machine tools, where internal hex installation helps keep the joint accessible. Alloy steel supports strength-focused fastening where clamp load and repeatable assembly are important. The combination of product name, size, material, and verified head data improves search clarity for engineers and buyers. Technical Highlights Material: Alloy Steel Thread: 5/8-18 Length: 9 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.