Does my lathe motor need bearings replaced?

The wavy washers are there to allow the armature to float axially so that when running it find its magnetic centre. if a motor is forced to run out of magnetic centre it will run hot and noisy. it allows the machining tolerances to be rather loose.
 
Downunder Bob said:
The wavy washers are there to allow the armature to float axially so that when running it find its magnetic centre. if a motor is forced to run out of magnetic centre it will run hot and noisy. it allows the machining tolerances to be rather loose.
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Yes, also to allow for thermal expansion of the shaft length. But this is usually in the 0.040" range, 1/2" is pretty extreme. That much I think warrants investigating. Some motors have snap rings either on the shaft or in a groove on the bearing itself for locating. One of those failing could result in excessive end play. Some use bakelite washers to shim for end play and they sometimes fail with age.
 
Alright... I had some time to take the motor out of the lathe, which was a giant PITA. I ended up discovering that a panel came off the lathe REALLy late, so I ended up trying to wrestle it through a hole that was only slightly too small. I FINALLY got it out though, and started tearing it apart:

First, I gave it a wipe down, and took this picture (and of the data plate):

IMG_20191223_155744.jpg
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I used a pulley puller to take off the toothed pulley, and took off the rear fan guard. The pulley side ended up coming off pretty easy:
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The rear fan I ended up breaking unfortunately (it was tac welded to a collar that was held in by a hidden-in-dirt set screw) using my pulley puller. Hopefully I can just flatten it out and JB weld it back together (or would there be a source of replacements?).

IMG_20191223_161416.jpg

THEN, the other endcap came off. Bearings on each side are the greasy on 1 side, sealed on the other kind, and had some 'grit' to them. The pulley side (the one with an accessdoor!) had been greased it seems, but the other had a much older grease in it:
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I was able to pull the back bearing off pretty easily, so the whole shaft assembly came out. It seems REALLY clean inside:
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I was able to pull both bearings out reasonably easily. I ended up having to grind my pulley puller a little to get in to the pulley side, but it worked.
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There was only a SINGLE wave washer on 1 side, I suspect the other should be in there too? There was a decent amount of play (I think my 1/2" was way more than it really was... I was able to move it by hand ~1/16" of an inch).

Bearing #s seem to be (fan side): 6206 C3, and pulley side: 6307 (also seemingly C3).

First, where is the easiest place to get replacements that I could also get wave washers too? Could I possibly replace these with fully sealed bearings so I don't have to worry about the grit? Does anyone know if that rear fan is replacable, or if I should just try to JB weld it back together after bending it flat again?

Thanks!
 
The wavy washer is usually only on one end of the motor. Replacement fans are usually available for most Baldor motors. I would not try to repair the broken one, almost any repair would likely throw it out of balance.

A local bearing shop should have both, or any of the normal online suppliers like McMaster.
 
i concur with not trying to JB the fan.

if you have means to tack weld the fan back into position, you may be able to save it that way
but adhesives or epoxies wouldn't stand up to the job.

get a quality brand of bearing.

SKF
FAG
INA
Fafnir
NSK
NTN

are all quality bearings.
available on ebay, amazon, Motion Industries, Kaman Bearing, King Bearing, McMaster Carr, Zoro Tools, Grainger, etc.
 
I note that the broken fan is the external one... It doesn't seem like it actually does anything though, the motor itself seems sealed, but this fan just sits out the back..

I picked up a pair of ZZ c3 bearings for it, a replacement fan that looks like the right one, and a new wavy washer, so hopefully it'll go back together alright :)
 
That external fan cools the motor by cooling the casing. the casing gets hot by conduction from the internals and by cooling the casing the internals can be kept at a safe temperature.
 
Downunder Bob is correct, that's why these motors are called TEFC, stands for "Totally Enclosed Fan Cooled"
 
Everything about this motor seems like overkill for me, so I'm not particularly concerned. I DID find what looks to be a replacement, so that will be here in a bit more than a week.

I did note that the motor wires aren't obviously marked, which is going to be a difficult time too... I ended up pulling them apart while dragging it out of the lathe, so at one point I need to figure out which is which!

At least the set of 3 that need to be connected to each other are still together, so I only have 6 to identify.
 
Carefully clean the wires and look for numbering on them. Don't us any solvents to clean them. Sometimes the wire numbers are printed on the wires, but unlike the wire data (gauge, temp rating etc.) that is often under a clear layer, the wire numbers are printed on the surface and can be wiped off very easily if the wrong cleaner is used..
 
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