How to Measure Carbon Brushes and Find a Replacement

Can’t find replacement carbon brushes for your power tool or machine? Been told the original brushes are discontinued?

At Top Deals Online, we may already stock a suitable replacement. Sending us accurate measurements, clear photographs and your machine’s details helps us check our range and identify possible matches.

Use our illustrated carbon brush measuring guide below, then send your information through our Contact Us page. You do not need to know the original brush part number to make an enquiry — send us the information you have, and we will let you know whether we need anything further.

Measure in millimetres. Photograph the complete brush. Include your machine’s model details.

Before you measure your carbon brushes

Switch off your tool and disconnect it from its power supply. Unplug mains-powered tools or remove the battery from cordless tools before inspection or maintenance. Follow the manufacturer’s instructions, and use a qualified repairer when removal requires work you cannot carry out safely.

Use a digital calliper where possible and record all measurements in millimetres (mm). Measure carefully rather than rounding to the nearest whole number. Keep the original wire, spring, cap and connector attached so you can photograph the complete assembly.

Is your brush worn or broken? Tell us. A worn brush’s remaining length is not its original new length. Measure what is left and describe its condition rather than guessing how long it used to be.

Step 1: Measure the carbon block

For both brush styles in the illustration, begin with the three dimensions of the carbon block itself. Do not include the wire, spring or metal fittings in these measurements.

Guide number	Measurement	What to measure
1	Carbon length	Measure from the working contact end of the carbon block to the opposite end, where the wire enters. Tell us whether this is a worn or unused brush.
2	Carbon height	Measure the carbon block’s height as shown by the red arrow in the guide.
3	Carbon width / thickness	Measure the remaining dimension through the block, from front to back. This is separate from its height.

Label each measurement clearly rather than sending three unlabelled numbers.

For example: Length: 12 mm, worn. Height: 8 mm. Thickness: 5 mm. These are example measurements only.

Step 2: Measure the spring, wire and fittings

Choose the style that most closely resembles your brush. If yours looks different from either illustration, send us photographs rather than trying to force it into one of these categories.

Type 1: Copper wire inside a spring, with a brass end cap and tabs

Along with the three carbon block dimensions, provide:

4 — Brass cap width, from tab to tab
Measure across the complete brass end cap, including both projecting tabs. Do not measure only the round centre section.

5 — Spring and wire assembly length
Measure from the back of the carbon block to the far end of the brass cap. Leave the spring resting naturally, without compressing or stretching it. Exclude the carbon block itself.

Include a clear photograph showing the spring, wire and shape of the brass cap.

Type 2: Exposed copper wire with a female spade connector

Along with the three carbon block dimensions, provide:

4 — Wire length
Measure from the back of the carbon block to where the metal connector begins. Do not include the connector body in the wire measurement.

5 — Connector height
Measure the outside height of the female spade connector, as indicated in the guide.

6 — Connector opening / slot width
Measure across the opening that receives the mating flat terminal. This is different from measuring along the connector body. Include a photograph looking directly into the opening; if it is too small to measure accurately, send the photograph rather than guessing. Connector specifications distinguish mating-tab dimensions from other terminal dimensions.

Do not bend or open out the connector to take a measurement.

Step 3: Send clear photographs and your machine’s details

Our Contact Us form allows you to upload up to three files with your enquiry. A useful set is a photograph of the complete brush, a close-up of its cap or connector, and a clear photograph of the machine’s identification label.

Please include the brand, full model number, voltage and any original brush part number you have. Copy any additional type, article or identification numbers from the label too.

The complete model details matter. For example, different versions of a tool can have different part requirements, even when the main model name looks the same. Our Help Me Find My Model page explains where to look for these details.

Photograph any markings on the carbon block and show unusual features such as grooves, angled ends or additional fittings. Keep the photographs well lit and in focus.

Tool or machine brand:
Full model number:
Type / article / identification number, if shown:
Voltage and wattage, if shown:
Original carbon brush part number or markings:

Brush style: Type 1 / Type 2 / Other
Carbon length in mm:
Carbon height in mm:
Carbon width / thickness in mm:
Brush condition: Worn / Broken / Unused

For Type 1:
Brass cap width, including tabs, in mm:
Length from back of carbon to end of cap in mm:

For Type 2:
Wire length in mm:
Connector height in mm:
Connector opening / slot width in mm, if measurable:

Other information:

eave any unknown fields blank and send us what you have.

Can you help with discontinued carbon brushes?

We may be able to help, even when the original part is no longer available.

Send us the old brush’s measurements, photographs and machine details. We will compare the information with our range and check whether we can offer a suitable replacement.

We cannot promise a match for every tool or machine, but the information in this guide gives us a useful starting point.

Are carbon brushes with the same dimensions interchangeable?

Not necessarily. Matching the size is only part of identifying a suitable replacement.

The carbon material or grade, brush profile, spring arrangement and electrical connections also need to suit the application. Photographs and measurements help us narrow down the options, but they do not establish compatibility on their own.

Please check with us before ordering a brush simply because its dimensions or appearance seem similar.

What if I do not know the model or part number?

You can still send an enquiry. Provide clear photographs of the brush, its measurements, and any labels or markings remaining on the machine.

Tell us what kind of machine it is and include any information you already have. We will let you know whether further details are needed before we can recommend a replacement.

Ready to check for a replacement?

Send your carbon brush measurements and photographs to Top Deals Online.

Visit our Contact Us page, select Carbon Brushes, enter your details and upload your photographs. We will check whether we have a suitable replacement available or need more information.

Clear photos + accurate measurements + machine details = a better starting point for finding the right match.