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9" SM Utilathe Restoration

trlvn

Ultra Member
So, what do you figure? Is this motor worth restoring or not?
If it was up to me, YES.

A 3/4 hp motor is pretty usable size. Bearings are really quite cheap and not difficult to change. A little WD-40 or brake cleaner and the outer case will look just fine. When used intermittently like in a lathe, these fractional horsepower motors last for many decades. Maybe the start capacitor will need to be replaced. That too is dead simple and inexpensive.

On another forum that I follow, they refer to the "rat hole". As in: "Doncha have a motor or six squirrelled away in the rat hole?" [Mixed metaphor, I know.] Along with pulleys of all sizes, some SOW cable, magnetic and manual motor starters, locking plugs and receptacles, etc, etc.

Maybe thats just me.

Craig
(I'm down to 2 motors in my rat hole. I've been hearing the siren song of the auction--"good stuff, cheap!")
 

YYCHM

(Craig)
Premium Member
Will you use that motor in 5 years?

If it's worth putzn with, I'll probably re-mount it on the lathe and use the 1/2 HP as a backup.

NEWSW.JPG

Ooooops. Had a little miscalculation with regard to available cable lengths here. I intended to mount that switch vertically. Oh well, it was intended to be an in term solution until I get the 3/4 HP functional again.

BTB - That FWD/STOP/REV drum switch has three back wires and one green wire coming out of it. How the heck are you supposed to know how to wire that thing up????
 

kevin.decelles

Jack of all trades -- Master of none
Premium Member
Compare an old motor to a new one..... is keep the old and do the bearings.


Sent from my iPhone using Tapatalk
 

Brent H

Ultra Member
Open up the old motor and change out the bearings as a learning exercise. The. New bearings on. 1/2 hp to 3/4 motor should be about $20. - great learning :p
 

YYCHM

(Craig)
Premium Member
Open up the old motor and change out the bearings as a learning exercise. The. New bearings on. 1/2 hp to 3/4 motor should be about $20. - great learning :p

It's got grease nipples over the bearings? What am I going to find in there? Are a bunch of ball bearings going to fall out?
 

Brent H

Ultra Member
Nope, probably the old school type open cage bearings, shielded one side bearing, shielded both sides or a sealed bearing that should of had the lube seek removed

Worst case is a sleeve bearing that has packing and wicks for lube. - argh! That is like I have for the tool grinder - it is for spindle grinding - very old but runs great with new felt
 

Brent H

Ultra Member
Get the number off the bearing - 6203, 6405 etc and you can order new ones - get the radial sealed type. So if you have a 6207 zz that is a double “shielded” bearing. A bearing with Z would be one shield. Typically the one shield goes towards the electrics. Easier to get a 2 RS bearing and be done with it.
 

YYCHM

(Craig)
Premium Member
Open up the old motor and change out the bearings as a learning exercise. The. New bearings on. 1/2 hp to 3/4 motor should be about $20. - great learning :p

Ya, I'll haul her out back tomorrow and clean off the grung, then look at how to open it up. Time to get my feet wet alright.

I gave the lathe a test run with the 1/2 hp installed tonight. The abated vibration does show in the finish. I didn't notice any lack of power taking 0.02" cuts. Loving this HSS tool I ground, should have tackled that learning experience two years ago.
 
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YYCHM

(Craig)
Premium Member
Well...… this was a bit of a struggle

DISSASEMBLED.JPG

Started at 8am this morning trying to clean off the grunge on the outside of the motor. What ever that stuff is, brake cleaner had no effect on it. All the brake cleaner accomplished was to flush away what ever the wire brush managed to lift. Spent a good hour and a half working at it.

Pulled the bearing caps off (The shaft end one is lower left in the image) . Well the bearings were well greased so no worries there. Now you can push and pull the shaft and see that the bearings will move in the end covers, so looks like those have to come off next.

The shaft end cover came off easy-peasy. Now the rotor wants to come out but something in there is holding it back. Hmmm..... must be that centrifugal switch you hear click when it's winding down.

Well.... the back cover (electrical end) gave me no end of grief. Could get the start of a hair line crack going but nothing wide enough to pry it off. I tapped and pulled for an hour to no avail. Finally I took a utility knife blade and tapped that into that hair line crack and she started to open up. Finally it popped off.

Disconnected the switch assembly and out came the rotor, switch and bearings. Phew.. it's now 12:45 pm.

As for the bearings, I'm not perceiving any issues what so ever with them. Appear tight and turn freely.

So dunno now? Replace them anyways?

Any suggestions as to how clean the crud out of the cage? Blowing it out with compressed air is the only thing I can think of.
 
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YYCHM

(Craig)
Premium Member
Filthy job...….

CLEANEDUP.JPG

But all cleaned up now. Brake cleaner, brushes, and compressed air got her done. You can actually see the wire color coding now. Everything was black before. Got dirty clear up to my elbows. Haven't had that much fun in a long time LOL. SWMBO will probably have a choice word or two about this shirt though:oops:

Now to figure out how to remove those bearings. The only pullers I see on the PA website are gear pullers?
 
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Brent H

Ultra Member
Hey Craig,

if you push, pull or twist the outer casing on those bearings do you notice any movement between the outer and inner race? When you rotated them, any gritty or harder to turn spots? If you have cleaned them out, will they spin and go for a long time or just a revolution or two and then stop? Any signs of corrosion or pitting on the balls? Any signs of the bearing spinning in the outer housing?
Recommend replacing them with sealed bearings. So on the race of the bearing will be some numbers - when you get new bearings ask for xxxx 2RS for example.

make sure to gently clean off the centrifugal switch contacts before re-assembly.
Notice that your motor is open to atmosphere (the slots on the back plate). That would be a typical drip proof type motor - that fan on the shaft draws air across for cooling. It will also draw oil and swarf and other crap. - if you recall from my lathe post I removed a bunch of swarf and a drywall screw from the old motor. I now have a shield that keeps the swarf at bay but allows proper air flow.
 

YYCHM

(Craig)
Premium Member
Hey Craig,

if you push, pull or twist the outer casing on those bearings do you notice any movement between the outer and inner race? When you rotated them, any gritty or harder to turn spots? If you have cleaned them out, will they spin and go for a long time or just a revolution or two and then stop? Any signs of corrosion or pitting on the balls? Any signs of the bearing spinning in the outer housing?
Recommend replacing them with sealed bearings. So on the race of the bearing will be some numbers - when you get new bearings ask for xxxx 2RS for example.

make sure to gently clean off the centrifugal switch contacts before re-assembly.
Notice that your motor is open to atmosphere (the slots on the back plate). That would be a typical drip proof type motor - that fan on the shaft draws air across for cooling. It will also draw oil and swarf and other crap. - if you recall from my lathe post I removed a bunch of swarf and a drywall screw from the old motor. I now have a shield that keeps the swarf at bay but allows proper air flow.

I haven't cleaned the grease out of the bearings. Should I do that before passing judgment as to their condition?

I did find some fine swarf in there but mostly black sooty stuff as if it had ingested a smoked belt or two.

If I get sealed bearings, can I remove the grease fittings and plug the holes with set screws?
 

RobinHood

Ultra Member
Premium Member
Craig, while you have the motor apart for new bearings, I would address the rotor shaft as well. That is some chewed-up, sad looking piece...

6DAD87B6-2B9B-4EE9-AFDE-40E7703D4D9B.jpeg

pulleys will fit better as well. Turn it between centers on your lathe to clean up all the chowder marks. You will either have to sleeve the pulley or the shaft to make up the difference.
 

YYCHM

(Craig)
Premium Member
Craig, while you have the motor apart for new bearings, I would address the rotor shaft as well. That is some chewed-up, sad looking piece...

pulleys will fit better as well. Turn it between centers on your lathe to clean up all the chowder marks. You will either have to sleeve the pulley or the shaft to make up the difference.

Ya, I was wondering if that shaft didn't defeat the bearing upgrade. I suppose I could turn it down to 1/2" and re-cut the keyway on the mill. 1/2" would at least be a common size. I have a motor pulley that needs to be sleeved, so I could sleeve that to 1/2" to mate up.

Project creep LOL.
 

YYCHM

(Craig)
Premium Member
Got the motor bearings off with the help of @BMW Rider , thanks Ed. Less than a minute a piece with the right tool.

BACKBEARING.JPG

They are both labeled the same and measure the same. 0.665 ID, 1.574 OD.

After cleaning the grease out there is a distinct difference in the feel of the front v.s. back bearing.

The back bearing spins freely and goes to town with compressed air turning it.

The front bearing...… well it feels pretty gritty and doesn't react to compressed air at all.

So.... take them to a bearing supplier and ask for suitable sealed replacements? I'll be looking at $20 each or $10 each?
 

RobinHood

Ultra Member
Premium Member
You sure you measured the ID correctly? Maybe measure the shaft‘s bearing journal instead?

Based on the OD, it looks like a quality 6203-2RS deep groove ball bearing would work.

6203 - 2RS is 40mmm OD, 17mm ID and a width of 12mm

https://www.skf.com/au/products/rol...ings/deep-groove-ball-bearings/productid-6203

PA has some cheap ones - not my first choice; would do in a pinch, however. I’d go for SKF Explorer (not their cheap line), NTN, NACHI, ore something along those lines.

https://www.princessauto.com/en/detail/bearing-6203-2rs/A-p3850658e
 
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YYCHM

(Craig)
Premium Member
Ah.... you're right 17mm and 12mm wide.

So I guess if I'm going to turn the shaft down I had better do that before investing in bearings in case things go sideways:( Turn her down to 1/2" sound ok?

BCENTERS.JPG

POORFINISH.JPG

Man that interrupted cut across the key way just kills attaining any semblance of a nice finish. I've had to slow the machine down to 250 RPM just to get something close to reasonable. The image depicts 250 RPM, carbide tool, 0.003" cut using the power feed at it's slowest setting. Not great by any stretch of the imagination.
 
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