Shoulder bolts are used as bearings and spacers. Their applications number many: as shafts for cam rollers and other rotating parts, as pivots and stud bolts, and as bearing pins for swing arms, links and levers. Shoulder bolts have a cylindrical head, a smooth cylindrical shoulder and a short threaded section. A small area between the threads and shoulder is undercut, which allows for a tight fit against the mating surface. They are also known as: stripper bolts, axle bolts, shoulder screws, hexagon socket head shoulder screws. Shoulder bolts are used with nuts and internally threaded (tapped) holes.