External Tooth Lock Washer

An external tooth lock washer has teeth on the outside edge that bite into the mating surface to resist loosening. It is used under a nut or bolt head to provide vibration resistance.

An external tooth lock washer sits under a nut or bolt head and its teeth bite into the bearing surface to resist loosening. It often matches a bolt or screw of the same thread and a nut of the same class. A spanner or socket usually tightens the assembly.

Zinc plating gives a thin, sacrificial coating that protects steel from rust in indoor and mildly corrosive conditions. Galvanising provides a thicker zinc coating for outdoor and more corrosive environments. Stainless steel washers are often supplied without additional coating.

This kind of washer is often made in stainless steel, including grades 304 and 316, or in steel. Stainless steel offers corrosion resistance, while steel grades can be zinc plated or galvanised for protection.

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 and a material test certificate. On receipt, check the tooth profile, inner diameter and outer diameter. Confirm the finish is uniform and free from damage.