I have an older 9" Delta table saw (my father got it in the early '70s
I believe) that refused to start working when I went to do a couple of
quick cuts on it. A 15 minute escape into the shop turned into an hour
and a half repair session (isn't that always the case), and the problem
turned out to be my motor brushes not making solid contact with the
I fixed that problem, and discovered that while one of the brushes was
nice and smooth, the other one was not. About 10-20% of it was nice and
smooth like the other one, but the rest was rough, and looked like it
had been chipped off. My questions are:
1) Will this slightly chipped brush aversely affect my table saw's
2) Can I repair the brush I have, or should I try to find a
Find a replacement brush and burnish the commutator with copper cleaner
from the kitchen. If there are any commutator bars that feel rough they
can be smoothed with a very fine file.
If that doesn't help you may have to replace the motor or find a [rare]
motor repair shop that will rebuild.
The chipped brush is not an issue. Why the brush chipped is an issue.
It could mean that the armature is gone short (look at the commutator
for a 'burnt' looking bar that may also be deformed). Could mean
that the bearings are sloppy and the armature is vibrating. Or it
could be that the brushes were just sticky and the motor needs a good
For cleaning it would that copper cleaner mentioned by Bugs be a good
I just realised that I didn't mention the why behind the brush not
contacting the motor. The copper wire that comes out the back of the
brush had been twisted up (like how you would twist up a rope to make
it shorter), and that was preventing the spring from pressing it into
contact with the commutator (did I use that correctly?). Once I
untwisted the brush, the wire loosened up and everything worked as it
I'm kind of hesitant to do too much to this saw, since it's over 30
years old, and I can't afford to purchase a new one, so the less I
monkey with its guts, the happier I'll be. If, however, giving the
commutator and the rest of it a cleaning would make it run better, I
wouldn't mind delving into it.
Thanks for everyone's responses!
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