Serrated Lock Washer

A serrated lock washer is a thin washer with teeth on the inner or outer edge. The teeth bite into the mating surfaces to resist loosening from vibration.

A serrated lock washer sits under a nut or bolt head and bites into the surface to resist loosening. External teeth grip the outside of the joint, while internal teeth grip around the fastener. It is matched to the thread size of the bolt or screw and used on electrical, automotive and general assemblies.

This kind of washer is often made in steel, stainless steel 304 or stainless steel 316. Steel washers may be supplied with a coating for corrosion resistance. Stainless steel grades are chosen for outdoor or corrosive environments.

This is a general guide to checking this kind of part. It says nothing about any supplier's parts.

Ask for a certificate of conformance for the material and dimensions. On receipt, check the teeth for sharpness and the washer for flatness. Confirm the inner or outer diameter matches the fastener.