Description
The main role of flat washers is to increase the size of a screw’s bearing surface area and reduce the surface pressure applied on the fastened object. Looseness can result when the bearing surface sinks under the surface pressure, so using a flat washer to reduce the surface pressure is very effective. This is especially crucial if the contact area between a screw’s bearing surface and the object being fastened is small when fastening to a slot, for instance, or if the object being fastened is made of soft material such as wood, aluminium or resin.