Help!-Pulley Frozen on Unisaw Motor Shaft

[Erica Bailey]

Does anyone have any suggestions for how to loosen a motor pulley that is frozen on the shaft? I've loosened the set screws and need to move the pulley toward the motor in order to align it with the arbor pulley. I've knocked it with a mallet, but am afraid to knock it too hard. I've read that excessive force may damage the motor's armature bearings.

[Bill Geibe]

Hi Erica,

The first step would be to give it a lengthy soaking with a penetrating oil like PB Blaster or one of several others. Also, make sure that no one doubled up on the set screws, putting one on top of the other.

Another trick might be to (carefully) put a puller on the pulley and try to get it moving the other way first.

Removing the motor from a Unisaw isn't too involved, so doing that first might help (but the motor is heavy). Once the pulley is off, you can clean things up so the problem won't happen again.

Bill

[ray hampton]

when you or I smack a pulley on one side , we end up cocky the pulley on the shaft, you can rotate the pulley by hand while using a mallet or hammer to tap on the pulley

[Van Huskey]

Bill is spot on, the puller is mentions is a gear puller.

[ian maybury]

Just be careful that the pullers is bearing on the hub of the pulley and not the sides of the 'V' grooves - they may bend or break. There's bearing puller sets with cross pieces with a scallop removed to fit around the shaft designed to do this job (Sykes Pickavant do one as a part of their hydraulic puller set) - two studs from the puller screw into holes in the cross piece.

A touch of heat (applied to the pulley and not the shaft) with a torch big enough to put heat in quickly may help too if the puller doesn't do it alone. The trick is to hit the pulley hard for a only a short while to get it well warmed up before the heat transmits significantly into the motor shaft. Watch out for the fire risk. (don't do it in situ) Timing is of the essence, in that if the motor shaft gets hot the expansion differential will be reduced, and you will risk damaging the motor - especially the seals and the bearings.

ian

[shane lyall]

Be extra careful with the mallet. I just replaced a pulley on my jointer because I wasn't. There made of cast in most cases so its soft and will break with a hard "tap". On the bright side, if you do trash it let's hope you don't, it can be replaced for about $50. If you have the motor out of the saw you can stand it on end so the PB Blaster or whatever soaks in quicker. Use gravity to your advantage here. Be careful with the torch as well as WD, PB and so on are flamible IIRC. The heat will help as much as anything. If it doesn't budge the first time keep hitting it with the penitrating oil after it cools and repete. Sometimes a few cycles will expand and contract it enough to break it free. Watch those seals and bearings in the motor as well. Hope it moves for you.

[Kyle Iwamoto]

Pull the setscrews all the way out, that gives direct access to lubricate the key with whatever penetrating oil you use. It also lets you look in there to see if there are 2 setscrews, which is pretty common on bigger motors.
If you have a large enough deep socket that fits over (around) the shaft, you could use the socket to hammer the pully loose. It applies even shock pressure to the entire pulley.
Use heat as a last resort.

[Charles Lent]

It's not a good idea to beat on the end of the motor shaft or to put any significant pulling force between the motor case and the shaft. Significant pulling or pushing with either a big hammer or other method can damage the motor bearings, and in some cases, the motor itself. It's best to use a puller or press that puts a steady force between the end of the motor shaft and the pulley and not put these pulling forces into the bearings. Make absolutely sure that ALL of the set screws have been removed and use penetrating oil in the set screw holes. Then use a 3 wing gear puller or possibly in combination with a bearing puller so that the forces are applied evenly to the pulley and to the end of the motor shaft.

Charley

[Bill Geibe]

Andrea,

I just had a thought about your problem: Most Unisaws use an iron motor pulley - about 3 1/2" diameter - and they are pretty sturdy. The ones with the lower RPM motors, however, use a bigger pulley - about 5 1/2" - that's made of pot metal. If you have one of these they are much more fragile and you would have to use extreme care in using a pulley puller. Using a puller attachment/splitter like Ian mentioned may work.

Then again, if it's one of the pot metal pulleys, heat may be more effective. Just don't melt the thing.

I saw an interesting post recently about someone else who had trouble removing a Unisaw pulley. It's about the 6th one down here: http://www.owwm.org/viewtopic.php?f=1&t=108836&p=736037&hilit=unisaw+pulley#p736037 I hope you don't have the trouble this guy did!

Bill

[Bryan Slimp]

Would it do any good to put the motor in the freezer for a couple of hours or days?

[Erica Bailey]

Thanks for all the input! I'm gonna try the gear puller and some penetrating oil first. I'll let you all know how it turns out!

[Jeff Duncan]

Would it do any good to put the motor in the freezer for a couple of hours or days?

No, because the pulley is still attached to it. The freezer method is the opposite of the heating method, you want to change the size of one piece while leaving the other alone. So the part in the freezer, usually the shaft, shrinks, while the bearing, (or in this case pulley), usually gets heated a bit to expand it. It doesn't change the size much, just enough to help them slip together. If they're still together and you change the temperature they will move the same amount.....so no help.

JeffD

[Jeff Duncan]

Erica, how far off is the pulley? I know there are some who believe they should be perfectly aligned, (and ideally they should), but if it's off something like 1/16" and was working fine I wouldn't go through the trouble.

good luck,
JeffD

[Erica Bailey]

Jeff,
It is off by 3/32". So not terribly so, but I wanted to get it spot on while I have the table off--its a pain in the rear end to get the table off! It's connected to auxiliary tables to the right and rear and then there's the unifence guide on the front! And of course, the table itself is heavy!
Erica

[Don Jarvie]

Get a piece of wood and place it on the pully resting on the motor shaft and give it a couple of taps. You'll be hitting the strongest part of the pulley and the wood wont damage it also. If it doesn't budge you may want to pull the motor out, get the pulley off and clean the shaft with steel wool and remount the pulley.

A couple of taps won't hurt the motor. You would really need to pound on the motor shaft to damage the motor.

[Erica Bailey]

Really dropped the ball on updating this thread! For those of you reading it hoping to find the solution that worked, here goes: I ended up leaving the pulley where it was, since the tool was functioning fine, i.e. there was no excessive vibration and no wearing out of belts, but I did order a gear puller, which has been a life saver for many other repairs around the shop. Amazing what the right tool will do! Though do be careful when using on aluminum pulleys: rather than pulling the pulley off the arbor, the force can bend the outer rim of the pulley. I think someone else mentioned that in this thread. Anyway, here's a late thanks to all who posted with suggestions and comments!