Internal Tooth Lock Washer

An internal tooth lock washer is a washer with teeth on the inside edge. The teeth bite into the mating surface to resist loosening from vibration.

An internal tooth lock washer grips a bolt head or nut and resists loosening from vibration. The teeth bite into the bearing surface when the fastener is tightened. It takes a bolt or nut of the same thread and sits under the head or nut on a flat face.

Galvanising gives a zinc coating that resists rust in outdoor and damp conditions. Zinc plating is a thinner zinc coating for indoor or lightly corrosive settings. Both finishes are for steel washers, not for stainless steel.

This kind of part is often made in steel or stainless steel 304. Steel washers are usually supplied with a zinc or galvanised finish for corrosion protection. Stainless steel 304 washers are used where rust resistance is needed without a coating.

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, finish and dimensions. On receipt, check the tooth form for sharpness and the hole size for fit. Confirm the finish is uniform and free from flaking or bare spots.