The shoulder bolts are also known as shoulder screws and stripper bolts. Shoulder bolts are screws with an unthreaded shoulder that is larger in diameter than the threads. The head has the largest diameter, the shoulder is described by its diameter and length, and the thread has a major diameter slightly smaller than the shoulder diameter. Shoulder bolts have a long, unthreaded, cylindrical shoulder that allows for the rotation of attached parts like pulleys, gears, moving parts of engines and mechanical assemblies, and rolling wheels. These screws are also used to attach stripper plates. They are also used as axels and pivot points.