electric motor rebuild

[nospamanobama]

ok, so i am starting the process to rebuild several 1960's era craftsman equipment, starting with the jointer.

i have the motor dissasembled, it wasnt too bad but needed a little cleaning. bearings roll nicely, and were not too dirty.

my question is how much and what kind of grease should i use? will regular bearing grease be ok? its made for very high temps ........

do i just need a little coating on the outside edge of the bearings where they must move agaist the inset of the housing?? there didnt seem to be a whole lot on them, not sure if thats normal or it has worn away with time.....

david

[DanG]

Bearings should NOT turn on the outside surface or the inside surface. The whole point is to do the turning on the ball bearings which you can see on some bearings, but I'm sure are covered by a dust shield on your bearings. They are permanently lubricated bearings, not serviceable - run till they growl or click, then replace them. It is failure of the "system" if the bearing's outer shell slips in its recess - Loktite makes a product to glue them in location if this happens.

[Lew Hodgett]

At a minimum, replace the bearings since you probably have already brinnelled the races getting the motor apart.

Brinelling will often go undetected until the motor is reassembled and the motor placed under load.

At that point, the motor will start sounding like a threshing machine.

Bearing replacement is standard practice when rebuilding a motor.

These bearings will be 203 size, the lowest cost bearings made.

Lew

[nospamanobama]

hmmmm...already reassembled......the motor actually came apart quite easily, and everything has been pretty gentle so i am hoping there is no brinelling

- only takes 1/2 hour or so if i have to replace them so i guess i'll have to see.

are you saying that anytime you take an electric motor apart you will damage the bearings???

[Lew Hodgett]

It is almost impossible to take a motor apart without transferring a static load from inner race across a couple of balls to the outer race when taking a motor apart.

The result is the balls brinell the races or leave pit marks in the races.

Standard practice is to replace the bearings and properly use an arbor press to reassemble the motor avoiding the load transfer across the bearings during re assembly.

Lew

[CW]

That would appear to be what he is saying but it is not true. You say the bearings feel fine. Did you use a hammer to take them out? If not, put them back in and be happy.

[clare]

Depends a lot on the motor though. Some can be taken apart by hand with virtually no prying or hammering, and assembled just as easily. In that case bearing damage would be unlikely - but When you have a motor apart a couple bucks worth of bearings is cheap insurance.

Usually takes more work to get AT the motor than to repair it.

>

[nospamanobama]

no hammer needed anywhere. slight prying to get the end caps off, but thats just what it takes and there is a little slot there just for that purpose. otherwise, i did not take the bearings off the shaft, the whole assembly just slipped right out. i did have to use the plastic handle of a large screwdriver to tap the pulley as i turned it so i could remove it from the shaft, then i wire-brushed the shaft and the little slot key thingy and put it back together.

guess i won't know until i put a load on it, but it will be a while as i have a lot of restoration to do to the rest of the jointer....