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Removing a stuck fan sheave

Posted: Mon May 18, 2020 5:45 pm
by Klfkyle
Apologies if this has been dealt with elsewhere on the forum. I’ve read many posts but have read about people getting unstuck at this point but have not been able to figure out how they did it...

I’ve just got an old Mark V and had it working, but then it stopped starting consistently and I could hear metal on metal. From reading other posts it sounds likely that the spacer between the fan sheave and motor is in trouble (once there was no load on the belts the same thing was happening and it’s very difficult to turn the motor by hand). Everything came apart as expected until I got to the fan sheave.

I’ve used penetrating oil to try and loosen it up. The photo should show the wedges I’ve got and tried to slide under to get some movement, but no go so far. The key doesn’t move—it’s supposed to come off after the sheave, right?

I understand there should be a set screw behind the sheave? I can’t get between the sheave and motor to see.

Any help would be much appreciated!

Re: Removing a stuck fan sheave

Posted: Mon May 18, 2020 10:17 pm
by DLB
If you remove the motor from the pan, normally four screws on the bottom, you should be able to see the set screw on the fan sheave. You want to be looking into the exhaust port of the fan, this will be more clear once you have the pan off. You'll have plenty of access to the set screw, the exhaust port is large.

You're correct that the sheave comes off before the key. That same setscrew is holding the key in the shaft.

- David

Re: Removing a stuck fan sheave

Posted: Mon May 18, 2020 11:01 pm
by benmcn
This is how I got a fused fan sheave off. You do need to remove the motor pan and set screw like DLB stated. Of course you do run the risk of breaking the fan.


https://www.shopsmith.com/ss_forum/view ... 57#p264057

Re: Removing a stuck fan sheave

Posted: Sun May 24, 2020 12:27 am
by beeg
There's a hole in the bottom of the case that's an access for that setscrew.