Shoulder bolts, also commonly referred to as shoulder screws or stripper bolts, are a specialized type of machine screw designed to function as a shaft or dowel. They enable the smooth rotation or sliding of attached components such as pulleys, gears, and various mechanical assemblies. A key feature of these fasteners is the unthreaded shoulder—a smooth, cylindrical section that has a larger diameter than the threaded portion. This shoulder determines the nominal size of the bolt and extends beyond the surface into which the threads are driven.

Thanks to its smooth surface, the shoulder provides a tight fit and prevents attached parts from rotating or sliding unintentionally around the screw. This precision makes shoulder bolts an ideal choice for applications where accurate positioning is critical, such as in high-tolerance machinery and assemblies. Whether you need reliable rotational performance or precise linear motion, shoulder bolts offer the stability and accuracy required for demanding engineering tasks.