Use a caliper to measure the carbon brush. If you don't have a a caliper, use a ruler
- Step 1:
Remove the carbon brush from the device (and from the carbon brush holder if there is one)
- Step 2:
The actual carbon brush is the black block or bar. It has three dimensions: Width (the shortest dimensions), depth (the second-shortest dimension) and length (the longest dimension, but this one is usally worn out). Fill in here the width
- Step 3:
Fill in the depth of the carbon brush - the second-shortest dimension
- Step 4:
Finally, fill in the length of the carbon brush. This is probably worn out, but you can estimate the original length by measuring the space for the carbon brush within your device or within the carbon brush holder. Usually, carbon brushes are about 2 or 3 mm shorter than their space.
It is no problem if the carbon brush is too long: You can easily adjust this with a file or sandpaper