5/16 x 3 1/2 Alloy Steel Socket Head Shoulder Screw (Stripper Bolt) with Nylon Insert is sized for tooling and fixture work where the shoulder is the operating surface, not merely a fastener shank. The shoulder provides the controlled interface, the 1/4-20 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.

For mold components, tooling inserts, plate retainers, and guided-motion rebuilds, the shoulder can act as the controlled surface while the nylon insert helps resist backing out under cyclic motion. The nylon element limits service temperature compared to an all-metal screw; ask about plain stripper bolts for hot tooling. When the application calls for stainless material instead of alloy steel, review 18-8 Stainless Steel Stripper Bolts.

Cold Headers supports die repair, OEM sourcing, and distributor requests for uncommon shoulder lengths and nylon-insert configurations. The size callout should be matched to the travel requirement, shoulder bearing surface, tapped hole, and access for the hex key.

Technical Highlights

• Shoulder Diameter: 5/16 in. nominal; 0.3105 max / 0.3085 min
• Shoulder Length: 3 1/2 in.
• Thread Size and Nominal Thread Length: 1/4-20 x 7/16 in.
• Head Diameter: 0.438 max / 0.419 min
• Head Height: 0.219 max / 0.209 min
• Hex Key Size: 5/32 in.
• Material: Heat-Treated Alloy Steel
• Locking Feature: Nylon insert in threaded end, providing prevailing torque
• Nylon Insert Diameter (P): 7/64 in.
• Nylon Insert Location (N): 3/16 in. (+/-1/2 pitch)

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