How and when to use washers effectively

What are Washers for? This guide is designed to introduce you to important component, covering:

Both plastic and metal washers are generally a disc shape, resembling a flattened donut. They’re typically used with threaded fasteners. Before the fastener is driven into its hole, the washer is placed on the bearing surface around the hole. The fastener is then placed on top of the washer.

Washers provide a longer life for the assembly you’re designing. Skipping on washers can dramatically reduce the lifespan of your components, so how your assembly is put together is critical. Ultimately, the lack of washers can lead to disaster for the products or components you’re producing.

A screw is a threaded fastener, and it’s here where washers really show their worth. Without a washer, a screw can damage the joint’s bearing surface when its threads dig into the material during tightening. 

Screw washers distribute the load. This is especially necessary when you’re driving into a soft material, such as wood or aluminium, which is vulnerable to stress-related damage. Washers for screws provide the resistance to the stress caused by the load. Screws with washers not only prevent damage, but also movement and corrosion. 

For the same reason they’re used with screws. Nuts and bolts add a particular challenge, however. If you don’t use a washer, the hexagonal shape of the nut and bolt can leave an indentation in the bearing surface. Washers for bolts prevent this from happening. 

A flange-headed bolt and nut present an alternative to a nut and bolt washer. The flange takes on the job of bolt washers, distributing the load and preventing damage.