5/16 x 4 Alloy Steel Socket Head Shoulder Screw (Stripper Bolt) with Nylon Insert provides a defined shoulder for controlled movement, accurate positioning, and serviceable fixture design. The important engineering feature is the shoulder, which supports positioning and movement while the threaded end retains the fastener. Typical applications include OEM production equipment, replacement hardware, tooling support, and machine repair. A nylon insert helps add loosening resistance where repeated motion, equipment vibration, or service conditions can work against threaded retention. Tool and die shops often evaluate this family when stripper plate travel or fixture alignment depends on a consistent shoulder surface. As a stripper bolt, it can support tooling and guided-motion applications where the shoulder is part of the operating interface. Common sourcing contexts include replacement maintenance, fixture construction, and OEM production support. Call Cold Headers at 773-775-7900 or email Sales@coldheaders.com for pricing, availability, or a quote.