Shoulder Washer

A shoulder washer is a washer with a raised sleeve or shoulder on one side. It insulates a fastener from the hole or centres it in a slot.

A shoulder washer distributes the load over a wider surface area. It is used under a fastener head when the supporting material is thin or when load spreading is necessary.

This kind of washer is often made in nylon, plastic or metal. The material choice affects insulation, load capacity and temperature resistance.

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 material and dimensions. On receipt, check shoulder height, bore size and that the washer sits square.