5/8-18 x 4 1/2 Alloy Steel Socket Head Cap Screw is a socket head cap screw for buyers matching an exact thread and length to drawings, repair records, or stocked hardware. The size callout supports replacement sourcing without changing the specified size when production-floor assemblies cannot accept a substitute fastener. The screw is useful across industrial facilities, power transmission, and material handling when a compact internal-hex fastener is required. The socket head form provides a cylindrical head suited to counterbores and recessed mounting pockets. Those verified dimensions support counterbore checks, tool selection, and replacement fastener review. Technical Highlights Material: Alloy Steel Thread: 5/8-18 Length: 4 1/2 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.