Most notably, washers protect the surface from damage during installation. They distribute the pressure and prevent the fastener from moving or corroding. Skipping on washers can dramatically reduce the lifespan of how your product is put together.
Washers and spacers are generally the same thing. Only difference is that spacers have a certain thickness so that they can be used to space something a certain amount. They are consistent in that thickness where washers aren`t.
Washers have been used as spacers in the past because they can get the job done. Most people only use washers as a temporary spacer until they can replace it with a more permanent, appropriate part. If you need a spacer right away, you can use the washer and then get a different spacer to replace it.
Washer, machine component that is used in conjunction with a screw fastener such as a bolt and nut and that usually serves either to keep the screw from loosening or to distribute the load from the nut or bolt head over a larger area. For load distribution, thin flat rings of soft steel are usual.
Metal washers are thin, disk-shaped plates with a hole that distributes the load of a screw, nut, or other threaded fastener. They can be manufactured for a variety of purposes and product requirements in industrial applications.
Washers may shift or move during the tightening process. This action affects the torque tension of the joint and can result in an inaccurate fit that will loosen or fail over time. In critical joints, even a small amount of movement can lead to disaster.
Washers are made from a variety of materials, the most popular of which are galvanized carbon steel and stainless steel. Carbon steel is stronger than stainless steel, but stainless steel will not rust or corrode like carbon steel can.
It is not a good practice to stack washers in a fastener joint.
Lock washers are needed when the fastener assembly is subject to vibration or wherever back off is considered an issue.
In some cases, they are used for very similar purposes and may even be interchangeable. However, a shim is mostly used as a spacer, while a washer is most often used to distribute a load for any type of threaded fastener.