Getting Bearing out of Electric Motor head

[TomB]

I am having to rebuild 4 or 5 motors after my shop flooded a few years back. They initially worked but then were idle while I moved and that seems to have caused them to set up. Motors that were submerged but then were run for 30 minutes seemed to survive. But those that were never submerged but close to the high water level are failing. Mostly from seized up gunk in bearings and/or centrifugal switches. It looks like the high humidity reacted with lubricants to make cement. Windings have all tested fine.

Anyway the one I now working on is a 3/4 hp Atlas solid armature motor for a horizontal mill. It is almost all apart and I've cleaned up the centrifugal switch, pulled one bearing (35 x15mm) off the armature shaft (it was frozen on shaft and it took all my strength on the end of 12" ratchet wrench and a good sized puller to free it), but the other bearing is retained in the motor head casting. The motor head has a 35mm thru bore with three things in the hole. From the exterior 1) is some sort of SKF sealing plug. (It resists a 20 ton press.) (2) is the bearing and 3) is a snap ring retention device. The bearing is loose and will slide quite easily between the SKF plug and the retention spring, about 5 mm.

The retention spring is about 1.5 mm (1/16 ") diameter and the grove it snaps into forces about 1 mm to remain extended, thus preventing the bearing from sliding out of the bore. The snap ring when inserted has about 1 cm gap between the ends. I can't imagine what tool could fit thru the gap and under the snap ring to pry the ring out of the groove. The SKF plug has the same ID as the bearing so it not feasible to just press the bearing out from the exterior side of the casting. Somebody must have seen this setup before and know how to attack it but right now I'm discouraged and baffled. (I took some pictures but my laptop seems to have lost the ability to read the little card.)

[CaptonZap]

https://www.harborfreight.com/hand-tool ... 66836.html

[10 Wheeler Rob]

Use a Dremal with a small diameter grinding tip. Slot the housing and cit through the ring opposite of the split in the ring. Take the two pieces out after grinding in two. Leaves a groove in housing, but it shouldn't hurt anything.

[TomB]

Use a Dremal with a small diameter grinding tip. Slot the housing and cit through the ring opposite of the split in the ring. Take the two pieces out after grinding in two. Leaves a groove in housing, but it shouldn't hurt anything.

Are you cutting from the exterior side of the motor head? Cutting from the inside which seems acceptable would require some sort of a right angle drive head which often seems like it would be useful but I've never seen it in the store.

https://www.harborfreight.com/hand-tool ... 66836.html

I have a set of Pick and Hooks but so far they have not been able to lift one end of the spring enough to get a screw driver under the end.

However, Thanks to both of you gentlemen.

[John Evans]

Straight in with a small carbide burr or a HSS right up to the ring a 1/4" away from the end of the ring. That should give you a place to get a pick under the ring.

[TomB]

The spring and bearing are out......

I had found that I could with a pin/hook rotate the spring so the gap was aligned anywhere but I could not get a hook under the spring. But triggered from the suggestion about cutting the spring (that would not have worked as it was needed to reassemble the motor) it occurred to me that I could drill a hole into the spring groove without hitting the spring. I measured it up about as carefully as I would a precision tool then bolted the head to right angle blocks to hold it square and vertical. Then mounted the whole mess on the drill press. The first hole wandered and broke the drill so I moved over a bit and went right through with a 1/8" drill. Then I rotated the spring so it covered the new hole and with a transfer punch I could go through the hole and push the end of the spring up. Once I got it hooked I could get a couple of small flat screwdrivers under the spring and walk it out of the grove like I was taking a tire off.

Once the spring was out I looked carefully at the groove. I was surprised that they had machined a round bottom groove which was why I could not get anything to slide under the spring wire. The hole I drilled is from inside the cavity where the power hooks up so it will even be covered. Finally I have no idea how the mill use to run. The first bearing I removed was lightly stuck but I could break it free with my fingers.Today's bearing was completely frozen and covered evenly with a thin layer of rust. When the mill was running the armature shaft must have been spinning in the inner race rather than spinning the inner race.

Thanks to all of you for helping. I'm sure that mulling over what you suggested lead me to the solution.

Tom

[10 Wheeler Rob]

Very nice solution to the problem.

[10 Wheeler Rob]

Very nice solution to the problem.

[spro]

This gets me back to remembering your horrible experience TomB . Keep kicking and obviously folks here care about you.

[spro]

All that considered, bump to the solution above.