Washers

A washer is a thin plate (typically disk-shaped) with a hole(typically in the middle) that is normally used to distribute the loadof a . Other uses are as a , spring (, wave washer), wear pad, indicating device, and locking device. washers are also used in (valves) where they form the seal that shuts off the flow of liquid or gas. Rubber or washers may also be used to reduce vibration when fastening fans tocomputer cases. Usually washers have OD (outer diameter) about twicetheir ID (inner diameter).
Washers are usually metal or . High quality require hardened steel washers to prevent the loss of pre-load due to after the is applied. orused in to stop the flow of water are sometimes referred to colloquially as ; while they may look similar, however, washers and gaskets are usually designed for different functions and made differently.
Washers are also important for preventing galvanic , particularly by insulating steel screws from aluminum surfaces.