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Could use some help: table saw motor issue and ID.

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Forum topic by Jofa posted 08-23-2015 01:57 AM 1178 views 0 times favorited 30 replies Add to Favorites Watch
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Jofa

272 posts in 1304 days


08-23-2015 01:57 AM

Hey folks.

I have an old Craftsman (Atlas Press) table saw that I got a few years ago and it’s been a fantastic tool. I use it quite a bit and its integral for my little business.

That said, I started to hear a couple of odd things with it. Towards the end of my day working today, I started to hear a bit of a screeching sound and when I tried turning it on a couple of times, it didn’t start turning and blew a breaker.

I removed the belt and the blade is spinning effortlessly so its not the arbor bearing on the saw (or whatever that’s called). :)

I blew out the inside of the motor and ran it without the belt. A couple of times it struggled to start (and blew a breaker) and a couple of times it ran. Still heard some metallic squeal.

I looked at the capacitor and its definitely old. I kind of know capacitors from working on amplifiers and this is an old Mallory in either a metal or phelonic casing. Blew that out as well (carefully because I assumed it had a charge).

So here’s a pic of the label on the motor. I’m wondering if it’s starting to go or if it needs bearings. Not sure how to ; that because I’ve never worked on a motor like this.

Any guidance is appreciated.

http://faraldi.com/pics/IMG_20150822_203425567.jpg

(Tried inserting the image but it looks like it was cut off. Please see the link)

-- Thank you Lord for the passion and ability to make things from your creation.


30 replies so far

View MrUnix's profile

MrUnix

4234 posts in 1665 days


#1 posted 08-23-2015 02:08 AM

That motor has sleeve bearings… when was the last time you oiled it? Hopefully they are still good (and/or haven’t scored the shaft too bad). They are a PITA to press out for replacement. Wouldn’t be a bad idea to crack the motor open and take a look at them (and the oiler felts), blow out the rest of the motor and clean up the centrifugal switch contacts while you are in there. The capacitor can be tested with a cheap multimeter to see if it’s good.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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Jofa

272 posts in 1304 days


#2 posted 08-23-2015 02:17 AM

MrUnix, thanks for the reply.

I will admit here that I haven’t oiled it. (Hides under desk).

Are there specific oil points? When you say sleeve bearings, does this mean there are no ball bearings in there?

-- Thank you Lord for the passion and ability to make things from your creation.

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MrUnix

4234 posts in 1665 days


#3 posted 08-23-2015 02:25 AM

No ball bearings… it has bronze sleeve bearings (bushings) that have felt oilers to keep them lubricated. There should be an oil hole above the bearing on each end bell… may have a little cap on it, may not. Use a non-detergent SAE20 weight oil or similar. 3-in-1 makes an oil specific for fractional motors (the blue bottle, not the red one) that works just fine.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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Jofa

272 posts in 1304 days


#4 posted 08-23-2015 02:45 AM

Thanks very much, Brad. I’ll hit HD tomorrow and give it a shot. Update to follow.

-- Thank you Lord for the passion and ability to make things from your creation.

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DocSavage45

7706 posts in 2308 days


#5 posted 08-23-2015 05:38 PM

Joffa,

Found your post in my deleted file, I apparently hit block sender on LJ’s notifiers when doing others. I would also recommend taking the motor apart, and cleaning it. If the saw is old and has been abused, might not be saveable? Grizzly sells a lot of motors you could need dimensions and capacity, and talk to tech support. They were very helpful when I wanted to upgrade my craftsman belt driven saw, as I needed more power.

I also would suggest lightly coating the shaft that goes into the sleeve with an oil based wheel bearing grease.

It has worked for me.

-- Cau Haus Designs, Thomas J. Tieffenbacher

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Jofa

272 posts in 1304 days


#6 posted 09-22-2015 09:13 PM

Hey guys.

Well, it was fixed for a while but I’m starting to have the same issue again.

I recorded a short video to hopefully give you an idea of what I’m experiencing. Basically, when the saw is turned on, it struggles to start spinning. Usually it trips the breaker.

I removed the belt and it’s starting but not smoothly. Also, the motor doesn’t sound very smooth when it winds down. I checked the bearing where the blade is mounted and it spins very freely so that’s not the issue.

If you could give this a look and offer ideas, I’d appreciate it. Thanks.

https://www.youtube.com/watch?v=ERPBTAZMcEw

-- Thank you Lord for the passion and ability to make things from your creation.

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MrUnix

4234 posts in 1665 days


#7 posted 09-22-2015 09:22 PM

Sounds like your centrifugal switch is malfunctioning, with something possibly loose making that noise when running. You really need to crack it open (easy to do) and check out what is going on in there. It will also give you the chance to blow out any accumulated sawdust/gunk that may be in there, examine the bearings and check the oilers. Might as well test the capacitor while you are at it – all you need is a cheap multimeter.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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Jofa

272 posts in 1304 days


#8 posted 09-22-2015 09:58 PM

^ ...and I begin Googling

:)

Thanks man. I did a recent cleanout and man, what a mess in there. I’ll open it up again and check.

-- Thank you Lord for the passion and ability to make things from your creation.

View bigblockyeti's profile

bigblockyeti

3668 posts in 1187 days


#9 posted 09-22-2015 10:10 PM

Sounds like the centrifugal switch is cycling every time but something’s certainly not right. Do you have a dial indicator that you could mount to check the runout in the shaft? It could be a bearing issue or something contacting part of the switch in the back of the motor.

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knotscott

7216 posts in 2842 days


#10 posted 09-22-2015 10:29 PM

My pool pump motor had a similar symptom that I cured by spraying down the centrifugal switch with WD40. As long as you’re going in to take a look, clean it out good, and spray it.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

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Jofa

272 posts in 1304 days


#11 posted 09-22-2015 11:00 PM

Thanks all.

So I took it apart and re-oiled the sleeve bearings. I also cleaned it and, after reassembling, removed the capacitor.

On the multimeter, the readings are almost nothing. A little jumping around but definitely not consistent. Almost like it’s drifting all over the place. I also used some sandpaper on the terminals and the connectors just to be sure.

I also checked to see if the switch was closed by doing a continuity test on the leads when the cap wasn’t attached. Seems to be fine.

So, I believe it’s the capacitor (which I just ordered from Amazon).

Now, the rough sound may be another issue. Probably because I didn’t originally know about oiling the bearings. In fact, the shaft does have a little bit of scoring but I know the motor runs and I’ll replace the whole thing shortly. Just need to get a couple of projects out at the moment.

So the question is, does my diagnosis seem accurate based upon what you folks have seen? Is it possible the capacitor is bad (or did I just read it wrong)?

Thanks again.

-- Thank you Lord for the passion and ability to make things from your creation.

View MrUnix's profile

MrUnix

4234 posts in 1665 days


#12 posted 09-22-2015 11:28 PM

Here is my quick-n-dirty method:

  • First, look for any leakage or bulging. If any, just replace it.
  • Set the multimeter to its highest resistance setting.
  • Make sure the capacitor is discharged by shorting the two terminals on it (just touch a screwdriver or anything metal across the terminals)
  • Measure the resistance across the two terminals. Doesn’t matter which lead goes where.
  • Reverse the leads and measure the resistance again across the terminals.

Possible outcomes:

  1. Meter does nothing (infinite resistance/open) = Capacitor is fried (open)
  2. Meter shows no resistance and doesn’t change when reversed = Capacitor fried (shorted)
  3. Meter jumps and then slowly starts going the other way. = Capacitor is probably good. It will jump to zero (short) and then start going to infinite (open) IIRC… been a while :)

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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Jofa

272 posts in 1304 days


#13 posted 09-22-2015 11:40 PM

Thanks Brad.

The meter didn’t start going to infinite for sure. Man I hope this new one fixes the issue. If not, I’ll be posting about suggestions on a new motor.

Actually, I’m gonna replace it in the near future. I know Harbor Freight sells them. Not sure if that’s the way to go though.

-- Thank you Lord for the passion and ability to make things from your creation.

View DocSavage45's profile

DocSavage45

7706 posts in 2308 days


#14 posted 09-23-2015 02:49 AM

Jofa,

Check out Grizzly for your motor, The service folk were very helpful when I was thinking about increasing the HP on my old belt driven Craftsman.

-- Cau Haus Designs, Thomas J. Tieffenbacher

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Jofa

272 posts in 1304 days


#15 posted 09-23-2015 03:51 AM

Doc, would this one work?
http://m.ebay.com/itm/161834950490

-- Thank you Lord for the passion and ability to make things from your creation.

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