Jigsaw carbon brushes question

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JJ1

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I was using my Bosch GST 135 BCE jigsaw yesterday. It began making a slight popping noise and the power became intermittent. I checked the brushes and noticed one of them was nearly completely worn down, whilst the other one had hardly worn down at all. As a quick workaround until I ordered some new brushes. I sawed the good one in half and placed each half in either side. Jigsaw is now working perfectly.

My question is: Is it normal for one of the brushes to wear down considerably quicker than the other one?
 

JJ1

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Anyone else know if brushes wear unevenly in a power tool? Surely most members would have replaced brushes in a tool at some point.
 

Doug71

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I had it on a Festool cordless drill once (back when they had brushes). It wasn't running properly so I checked the brushes, I remember when I took the first one out I thought "Well there's nothing wrong with them?" but when I checked the other it was "That'll be the problem then!".
 

Stuart Moffat

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it‘s possible that the less worn one was the problem causing the intermittency if either the carbon or a bit of the spring catches on the side, but I have only seen that once. Any which way replace the pair. Check if it’s possible that the commutator isn’t damaged as if damaged they can quickly trash the brushes, although if that happens it will trash both.
 

Inspector

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Here are a few pictures of the Shop Vac motor I mentioned in the second post.

It isn't meant to be taken apart but you can see that one brush never moved from new and the other went down until it couldn't anymore and the motor then cooked.

The picture below shows the end of the motor and you can see in the upper brush that it no longer shows in the pair of slots on the upper brush where it does show in the lower.
IMG_5435.jpg


Below is the lower brush that also shows the carbon brush in the little half-moon cutout just above the armature. It never moved from new.
IMG_5437.jpg


This picture shows the upper brush that was doing all the work and it barely shows in the half-moon cutout. Bad picture, you'll have to take my word for it. The top of the brush and spring are visible in it. There is about 7 or 8mm of brush left where the other side is close to 30mm.
IMG_5436.jpg


A motor will run on one brush, likely not as efficiently, until it can't make good contact and then it all grinds to a halt.

A good motor can probably be taken apart and fixed but this thing was never meant to be repaired so the vacuum became a scrap wood bin on wheels, the rest went to the scrap metal pile and the dumpster at the transfer station. I kept the motor as I bought another of the same and will check it soon to see if the brushes are wearing evenly and if not free them up and replace the shorter with the one from this motor.

Pete
 

Inspector

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What pray is a dumpster and a transfer station? Seperated by a common language again. :LOL:

Transfer station is the municipal waste drop off. They take recyclables (cardboard, paper, cans, bottles, plastics etc) wood waste that they get ground up for compost etc, green waste, metal and garbage that goes in a big bin, a dumpster. The dumpster gets hauled off to the big city dump/landfill and the recyclables and metal get picked up and hauled away to their respective destinations. Dumpster is another nickname for the big garbage bins outside businesses that private companies supply and empty for a price.

We together again? :)

Pete
 

clogs

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Phil,u need to watch more movies.....lol.....
Dumpsters are a great place for DUMPING dead bodies......
SADLEY, latley even babies.....
Here in Crete the houses have no bins as in the UK...we have dumpsters located at set, convienient places for the rubbish.....
also a good idea is that people put to the side of the bin anything that can be reused, furniture even whole kitchens...we recycled loads of good stuff from our house after the move....
even stuff gets taken within mins of leaving it....local people are poor in this area...so it all helps...
U see in my youth I was trained as a skip rat......hahaha...
 

JJ1

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Thanks everyone for your input. I've now received a pair of new brushes, all fitted and the jigsaw is working fine. It'll be interesting to see how they wear down in the future, but for now, the jigsaw is back up and running :):)
 

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