Shaft collars with a recessed set screw can be found in virtually any type of machinery and are frequently accessories to other components. Capable of fulfilling many roles, shaft collars often hold bearings and sprockets on shafts, situate components in motor and gearbox assemblies, and serve as mechanical stops.

They derive their holding power from their set screw, which is tightened onto the shaft. Ideally, the screw impinges, or “bites”, into the shaft when it is tightened, assuming the shaft is of a softer material than the screw. A shaft that is harder than the set screw will not support the impingement and the collar’s holding power will be greatly reduced.