Structural Washer

A structural washer is a flat round washer for bolted structural joints. It spreads the bolt load over the joint surface and covers a clearance hole.

A structural washer is placed under the head of a fastener or against a nut. It is used in various structural and general engineering applications.

Hot dip galvanising gives a thick zinc coating for outdoor and wet service. Black oxide gives a thin dark finish for indoor use where mild corrosion protection is enough.

Structural washers are often made in carbon steel. Some grades are quenched and tempered for higher strength.

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 mill test certificate for the steel. On receipt, check the hole size, outside diameter and thickness. Look for cracks, burrs or coating damage.