what are lock washers used for
Washers are used for multiple purposes when mechanical parts are assembled. Here are some usages : Some washers have a special design that attempts to help keep the nut and/or bolt from coming loose. Known as a lock washer these may be a split ring type, star type, wavey or any one of a number of other designs. A lock washer will be used with the part of the assembly that most likely could turn such as the nut. It could be used under the bolt head in instances where the bolt screws into threads in one part of the assembly. A washer is sometimes used to protect the surface of the assembled parts.