5-40 x 3/8 Alloy Steel Socket Head Cap Screw is specified when a machine assembly needs a high-strength alloy steel socket screw with predictable head and drive geometry. This size keeps the specified 5-40 thread and 3/8 in. length visible for service work where the exact thread and length are already defined. Applications often include engineering departments, power transmission, and assembly equipment, especially where counterbored or close-clearance mounting is required. Alloy steel supports strength-focused fastening where clamp load and repeatable assembly are important. The technical highlight block below retains the verified head diameter, head height, body diameter, and hex key data. Technical Highlights Material: Alloy Steel Thread: 5-40 Length: 3/8 in. Nominal Body Diameter: .125 in. Head Diameter: 0.198 in. min / 0.205 in. max Head Height: 0.121 in. min / 0.125 in. max Hex Key Size: 3/32 Drive Type: Internal hex socket Call 773-775-7900 or email Sales@coldheaders.com for pricing, availability, or a quote.