Centrifugal Motor Switch Noise Fix

glenn bradley

Member
Messages
11,514
Location
SoCal
I promised myself that if I ever did this again, I would take pics and share. I had a noise on my bandsaw that I traced to the motor centrifugal switch; easy fix. My cyclone started making a similar noise and based on my previous experience a few years ago, I went right to the switch. The noise is harmless; it is caused by the reverse-giggle-bearing rubbing on the doo-funny. In technical terms that means the plastic ring that pushes the spring-steel loop that opens the switch rubs enough to start an oscillation that creates a sound somewhere between a scrape and a squeal.Unplug your tool and remove the motor fan cap (three screws on mine)G0440-cent-clutch 1.jpgI mark the fan position with a felt pen and loosen the retaining screw. Remove the fan.G0440-cent-clutch 2.jpgRemove the clutch cover (two screws on mine)G0440-cent-clutch 3.jpgI mark the height and screw position before I remove the centrifugal assembly.G0440-cent-clutch 4.jpgG0440-cent-clutch 5.jpgG0440-cent-clutch 6.jpgPut some fine sandpaper on something flat and buff the flat surface of the pressure ring. Here I use 600 grit on my workbench top.G0440-cent-clutch 7.jpgRub some graphite into the flat face of the ring and re-assemble.G0440-cent-clutch 8.jpgMy bandsaw hasn't made a peep since I did this. Time will tell for the cyclone.
 
Last edited:
Thanks Glenn i never even thought about that. Of course to finish this thread off you left out one small detail and that was the audio file to be able to hear the sound. :) I am none the wiser as to the sound i should be looking for if i had the problem but i guess when it happens i will know. :)
 
Thanks Glenn i never even thought about that. Of course to finish this thread off you left out one small detail and that was the audio file to be able to hear the sound. :) I am none the wiser as to the sound i should be looking for if i had the problem but i guess when it happens i will know. :)

On mine it occurs during the last minute or so of rotation following shutdown. As the rpm's reach a slow enough speed, there is a click which is the clutch changing position and opening the switch. Once mine then slowed down to the right speed to induce the oscillation it goes:

--- (use you best little-girl falsetto voice and say) ---

Eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee!

On the bandsaw it was more of a scraping sound like someone sharpening a knife on a stone: swish-swish, swish-swish, swish-swish, swish-swish, swish-swish, swish-swish, swish-swish, swish-swish, swish-swish, swish-swish, swish-swish, swish-swish, swish-swish, swish-swish, swish-swish.

You'll know it if you hear it. It just sounds "wrong". The upside is that if it should occur it is a super-easy fix. ;-)
 
Last edited:
When I got my first lather I learned rather quickly that a TEFC (totally enclosed fan cooled) motor really is not totaly enclosed. In six years of use I once, only once, had to take the cover off, clean the sawdust out, spray liberally with WD-40 and resume using.
 
I've had to clean that out on my dads old craftsman radial arm saw a few times, and the one on my dust collector once.

Great tutorial Glenn!
 
Thanks for saving me a bunch of time troubleshooting. I followed your instructions on my dust collector and the rattle/squeal noises are gone!
 
When you use graphite close to electrical circuits, bad things can happen. It's conductive. Rather than graphite, use a very small wipe of synthetic grease on the plastic ring rub surfaces and the shaft where the ring needs to slide. Don't use so much grease that it can slide or fly off in chunks, just a very thin layer. Being synthetic, it won't change viscosity with temperature changes, and it won't harden up over time. You likely will never need to service the problem again in your lifetime.

Charley
 
I'm with you Charlie. I put a bit of graphite on my fingertip and rubbed it hard into the surface like I was paste waxing it. This may have been useless as when I finished there was no graphite color rubbing off (on a clean finger) ;)
 
Top