Thrust washers can be found in almost every appliance, machine, transportation conveyance, power tool, and recreational device that has moving parts, axles, bolts, pins, bearings, and rotating components. In their simplest form, thrust washers are long-wearing flat bearings in the shape of a washer that transmit and resolve axial forces in rotating mechanisms to keep components aligned along a shaft. Thrust washers are an economical alternative to rolling thrust bearings whenever forces velocities are moderate.
The need for thrust washers presented itself in antiquity almost as soon as the wheel was invented. These rugged washer shaped flat bearings are used to prevent wheels from moving sideways on axles whenever the bearing that handles the radial load such as a bushing or roller bearing has no specific provision for axial or thrust loads.