Mitre Saw Brush Replacement

April 27, 2009

I recently inherited a sliding mitre saw that needed a bit of work. The motor would no longer turn, alternating between doing nothing and arcing and sparking from the end of the motor when the trigger was pulled.

The first thing to look at with any motorized tool in this case are the brushes. Simply put, the brushes help transfer the electricity from the stationary part of the motor to the spinning part. Since the carbon brushes are constantly being worn away, eventually they will shink to the point where they are no longer able to apply enough pressure to transfer the electricity. This is why you get the arcing and sparking.

Thankfully, replacing brushes is one of the simplest repairs you can undertake on your tools. You will notice two round screws on opposite sides near the end of the motor. These screwcaps hold the brushes in.

One of two brush caps on my mitre saw

One of two brush caps on my mitre saw

I removed one of the caps and found a number stamped in the side. From here it was a quick ebay search with my saw’s model number and I had found my new brushes. The Tool Dude from thetooldude.com had the parts that I needed, and thankfully he shipped to Canada as well. For around $12 I had my new brushes purchased and on the way.

After about a week of waiting patiently, my new brushes showed up in the mailbox.

Replacement brushes

Replacement brushes

Here you can see how worn the old brushes were – over half of the material is gone! It is interesting to note what appears to be a thinner spring and copper wire on the replacement brush – they must be saving a fraction of a penny on each brush.

Old brush is on the left, new brush on the right.

Old brush is on the left, new brush on the right.

It was a simple matter of removing my brush caps, removing the old brushes and sliding the new ones in, and I was back in action.

Removing the brush cap screw.

Removing the brush cap screw.

The only part of this operation that you could possible do wrong would be to not properly line up the brass contact end into the slot that it goes into – on some motors this won’t matter, on mine I had to line up the protruding pieces on the side of the contact.

Inserting new brush.

Inserting new brush.

Along with a brand new blade, the saw is cutting as good as new! I’m glad I was able to delay the $750+ hit a new saw would have been. I will get a few years out of this saw, I think.

Next on the shopping list is a nice standfor my saw – no more fiddling around on the ground for me! Any stand that I buy will be universal, so I can continue to use it even if I upgrade my saw.

Leave a Reply