4 Types Of Washers: Definition And Benefits

Not many of us tend to put much thought into our washers, screws, nuts and bolts, but their features significantly impact their success. We also tend to use washers as an umbrella term, but in reality, many types of washers are helpful for different things. If you're not too familiar with the world of washers, we're here to help!

At Trade Warehouse, we specialise in providing our customers with all the information they need before they make a purchase so that you can get the best possible use out of your tools. We've compiled this complete washer guide to help you decide on the best washers for your project.

We'll be discussing the definition of washers, what we use them for, and the four types of washers and their benefits.

What are washers?

Before we get into the ins and outs of washers, it's essential to define washers. Washers are small round ring that sits on the shaft of threaded fasteners, such as screws and bolts. Washers provide additional strength by distributing the weight load evenly across fasteners, sitting between the surface and the fastener head.

Generally, you can separate washers into three categories. These are spring washers, plain washers, and locking washers. Typically, washers are made of mild steel or plastic and provide corrosion resistance, increasing the strength and durability of a fastener.

There are several ways that we protect washers, screws, nuts and bolts against damage from corrosion. Here's a quick guide:

  • Metal coatings: We use corrosion-resistant or protective metals like zinc, cadmium and nickel to protect against wear and tear. Zinc-plated washers essentially provide a layer to erode before the washer, increasing the washer's lifespan.
  • Electroplating: This process uses electrolysis deposition using silver or chromium as a protective layer.
  • Phosphating: Phosphating is a process that uses zinc phosphate as a resilient and abrasive surface to protect against corrosion.
  • Chemical plating: Chemical plating provides a high degree of protection against corrosion and abrasion using nickel phosphor alloy.

Why do we use washers?

Here's a guide to why we use washers:

Load bearing 

The most common reason we use washers is to distribute load across a larger surface area. While threaded fasteners are handy, they greatly stress the material around them.

Say you're using timber to build a shed, for example. If you're driving a fastener into the wood, you could risk splintering, damaging the structural integrity of the surrounding structure. A washer helps to redistribute that weight, minimising the damaging effects on the material surrounding it.

While you might not need a washer for some materials, we suggest using them for softer materials like wood.


It might seem strange to need a spacer when driving a fastener, but you might find them handy if you've got a particularly long fastener. Sometimes, you might find that the bolt or screw is longer than the object's depth.

When this happens, you'll need a spacer washer to provide a gap between the material's surface and the fastener's head. That way, you'll still have a firm hold without poking through the other side of the material.

Vibration absorption 

We can also use washers to dampen the impact or shock from vibrating machines. Usually, these types of washers are made from plastic, rubber or neoprene.

This soft material can absorb shock much more effectively than metal, protecting the integrity of the fastener and stopping objects from becoming damaged by strong vibrations.

Four types of washers

Now that you know what washers are and their key benefits, let's go through some of the individual types of washers.

1. Spring lock washer

Spring lock washers are a type of washer that is used to prevent a screw or bolt from loosening with severe vibration. A locking washer is a sub-type of a spring washer and is made of high-tensile steel, aluminium, stainless steel, and other alloys.

This helps the washer stay resilient against corrosion over a longer period. The spring lock washer's design helps prevent unintentional slipping from torque or vibration. Some spring lock washers do this by biting slightly into the base of the fastener.

One of the critical benefits of spring lock washers is that they have many applications. These washers are best for:

  • Transportation (trains, buses, planes, maritime transport)
  • Household appliances (washing machines, driers, etc.)

There are a few types of spring lock washers; here's a guide:

  • helical lock washers(a ring with uneven ends)
  • Internal tooth lock washer(teeth on the inside of the ring)
  • External or star washer (teeth on the outside of the ring)
  • Combination (teeth on inside and outside of the ring, providing comprehensive security)

2. Plain washer

Also known as flat washers, plain washers are the most common type of washer and consist of a flat ring with no locking function. The primary use of a plain or flat washer is to protect the surface material from the fastener, such as soft materials like timber.

We can also use a flat plain washer as an effective spacer when the fixing is too long for the material depth. Plain washers are usually made from 316 stainless steel.

3. Fender washer

A fender washer is another flat washer, except it has a much larger outer diameter than other flat washers. These are sometimes known as mudguard washers or penny washers. This allows the washer to bear a lot more load than other options, meaning they're beneficial for areas of high movement or heavyweight. While a standard heavy-duty washer has a diameter of 10 mm, a fender washer has an outer diameter of 25mm.

A fender washer also offers excellent protection against damage from the fastening, so it's suitable for materials like metal that scratch easily.

4. Square washers

A square washer is like a standard flat washer for all types of threaded fastening screws, but its outer shape is square instead of round. This handy washer allows the weight to be distributed on an equal surface area.

Square washers are called construction square plate washers, typically used for timber structures or flooring projects. The shape of the square washer also means that we can safely remove the screw without causing damage to the material.

Final thoughts

That concludes your guide to all things washers. We hope you feel more confident when selecting your perfect washer for your DIY project.

We have huge product availability here at Trade Warehouse and are proud to offer services for all your DIY needs, from screws and bolts to materials for your next building project.

As well as this, we have a massive stock of all your washer needs, from neoprene roofing washers to steel heavy-duty washers that suit all your project requirements. You can use our online filters if you're looking for a specific type of washer for your fixings. Our filters sort your selection by washer type, so you can quickly locate the perfect washer for your function.

You can also shop smart or through our online store and sort your product choice by price, so you don't need to sweat it if you're on a budget.

Make sure you check out the Trade Warehouse blog page, where we have a number of articles that discuss other DIY tips and tricks.

Frequently asked questions

Here are some answers to frequently asked questions about washers:

What are washers?

Washers are metal plates that sit on a bolt or nut to distribute the weight on the fixing. They sit on the fixing with a hole and separate the bolt or nut head from making contact with the surface.

What are spring washers used for?

Spring washers counteract vibration and absorb shock with their conical shape. This stops them from sitting flat against the wall and putting weight on the structure. This is particularly beneficial if you're working on machinery or structures that will move or vibrate, as the spring washer will stop the fixing from loosening over time.

What is the purpose of washers?

A washer helps to distribute the weight on a threaded bolt or nut. This makes the fixing more secure and ensures your project can withstand force. Washers can also be used as a spacer to sit between the bolt or nut head and the surface.