How to choose the right penny washer

Penny washers have a wider outside diameter than a standard flat washer of the same nominal fixing size. That wider face is useful when you want a broader bearing surface beneath a bolt or screw head, need to cover a modestly enlarged hole, or want a neater fixing face.

If you already know this is the washer type you need, start with the Jones DIY penny washers range. If you are not sure which option to order, use the checks below.

1. Start with the fixing size

The first part of the size describes the fixing the washer is intended to fit. If your bolt or screw is M6, start with an M6 washer. Do not choose only by looking at the outside diameter: a washer can have the coverage you want but still have the wrong centre hole.

• Check that the fixing is metric and confirm its nominal size.
• Measure it if the marking or original specification is unclear.
• Do not assume the largest washer will be the best fit.

Jones DIY currently has penny-washer product routes from M3 through to M12.

2. Choose the outside diameter

Once the centre hole matches the fixing, choose the outside diameter. A larger outside diameter covers more surface, but it also needs enough room to sit flat. Check for edges, corners, rebates, raised details, other fixings or curves that could stop the washer seating properly.

Check the live product page before ordering because product options can change.

When can a penny washer help with worn timber?

A penny washer can be useful where a nut or bolt head has made a local compression pocket, or where the surface of the hole is only slightly enlarged, provided the surrounding timber is still sound and the washer can sit fully flat.

If the washer rocks, bridges a split or sits partly over missing material, stop and repair or replace the damaged part rather than tightening it down.

3. Check the material

The Jones DIY penny-washer products checked for this guide are described as A2 stainless steel. That makes the material choice within the current range straightforward, but you should still confirm that A2 stainless is suitable for the conditions of the job.

• Check whether the fixing and washer materials are suitable together.
• Consider whether the job is indoors, outdoors, damp, coastal or exposed to chemicals.
• Follow any project specification that calls for a particular stainless grade, coating or finish.
• If the washer will be visible, check that the finish is acceptable.

Do not assume that all stainless grades suit every environment. If the job has a specified material requirement, follow that specification rather than choosing on appearance alone.

4. Match the washer to the job

Job problem	What to check
The nut or bolt head is marking the surface	Check whether a larger outside diameter gives a broader bearing face and still sits flat.
An old hole is modestly worn or enlarged	Check whether the washer covers the affected area without hiding a larger repair problem.
A bracket or panel needs a neater fixing face	Check the fixing size, available space, outside diameter and material.
You need several common sizes	Compare individual packs with the 75-piece assortment.

Different fixing styles

Hex nut on a through bolt

Place the washer between the nut and the surface when the nut is the part being tightened. The timber before-and-after above shows this arrangement.

Coach or carriage bolt

A coach bolt has a smooth domed head. In a timber through-fixing, the penny washer normally sits under the nut on the reverse rather than beneath the domed head.

Button-head machine screw

On a light, non-structural panel or trim fixing, a penny washer can provide a broader face beneath a low-profile screw head where the assembly allows it. The hole should be only slightly enlarged and the surrounding material must be intact.

This guide is buying help, not structural advice. If the fixing is heavy, safety-critical, load-bearing or part of a vehicle safety system, get the job checked properly before relying on a washer change.

Individual packs or an assortment?

Choose individual packs when you know the fixing size and outside diameter you use regularly. Choose the 75-piece penny washer assortment when a mix of common sizes is more useful than a larger quantity of one size.

Common mistakes

Buying by outside diameter only

The centre hole still needs to match the fixing. Start with the nominal fixing size, then choose the outside diameter.

Choosing the material by appearance

Two washers can look similar but have different material or finish specifications. Check the product details and the job requirement.

Ignoring the surface

A washer needs to sit flat. If the surface is split, soft, uneven, badly corroded or seriously damaged, the washer may only hide the problem.

Using a bigger washer without checking clearance

A wider face is only useful if it fits the available space and does not overlap an edge or obstruction.

Before-buying checklist

• The nominal fixing size.
• The washer centre hole.
• The outside diameter needed.
• The space available for the washer to sit flat.
• The washer material and job environment.
• Whether an individual pack or assortment is more useful.
• Whether the fixing point needs a proper repair or specialist check.