5/8 x 3 1/4 Alloy Steel Socket Head Shoulder Screw (Stripper Bolt) with Nylon Insert places the working diameter in the shoulder and the locking feature in the threaded end for press and fixture service. The shoulder provides the controlled interface, the 1/2-13 threaded end retains the part, and the socket head keeps installation access available from the top side. That nylon insert helps the screw resist backing out during cyclic shock, vibration, or press operation without implying permanent locking.

Designers often review this size for press tooling, blanking dies, stripper plate screws, and controlled-return hardware where a plain threaded screw would not provide a proper guide or pivot surface. Check the mating hole, die shoe thread, and working clearance before substituting another shoulder diameter or length.

Cold Headers is a Chicago specialty socket fastener distributor focused on exact-size sourcing for industrial replacement needs. We install the locking pellet ourselves; odd sizes and special requests are welcome. For repair work, verify the shoulder length, working diameter, threaded end, and locking-pellet position against the removed fastener.

Technical Highlights

• Shoulder Diameter: 5/8 in. nominal; 0.623 max / 0.621 min
• Shoulder Length: 3 1/4 in.
• Thread Size and Nominal Thread Length: 1/2-13 x 3/4 in.
• Head Diameter: 0.875 max / 0.853 min
• Head Height: 0.375 max / 0.365 min
• Hex Key Size: 5/16 in.
• Material: Heat-Treated Alloy Steel
• Locking Feature: Nylon insert in threaded end, providing prevailing torque
• Nylon Insert Diameter (P): 5/32 in.
• Nylon Insert Location (N): 1/4 in. (+/-1/2 pitch)

Call 773-775-7900 or email Sales@coldheaders.com for pricing, availability, or a quote.