3-56 x 1 1/4 Alloy Steel Socket Head Cap Screw gives engineers an internal-hex fastener for mechanical joints where socket engagement and dimensional consistency matter. The exact 3-56 x 1 1/4 size helps buyers align the fastener with service work where the exact thread and length are already defined. Selected for packaging machinery, machine tools, and engineering departments, it gives maintenance teams a searchable alloy steel socket screw callout. Socket engagement helps technicians apply installation torque from above the head in constrained layouts. Those verified dimensions support counterbore checks, tool selection, and replacement fastener review. Technical Highlights Material: Alloy Steel Thread: 3-56 Length: 1 1/4 in. Nominal Body Diameter: .099 in. Head Diameter: 0.154 in. min / 0.161 in. max Head Height: 0.095 in. min / 0.099 in. max Hex Key Size: 5/64 Drive Type: Internal hex socket Call 773-775-7900 or email Sales@coldheaders.com for pricing, availability, or a quote.