Belt Sander/Grinder Setup

[Dave MacDonald]

Hi there,

I've been using the Lee Valley / Viel Tools 1' belt sander/grinder recently. There's an almost imperceptible wobble in the drive wheel which (I think) causes a very perceptible flap in the belt at the back (interestingly, mostly on one side), and I can feel my blade knocking against the platen. This strikes me as undesirable. I can't, however, figure out what to do about it. It seems to me that a wobble can be caused only by a bent shaft, a bent wheel, or a wheel that doesn't sit squarely on the shaft. In all of these cases, I'm at a loss.

Or perhaps I'm missing something? Or perhaps a little bit of wobble and flap is to be expected? Any thoughts would be appreciated!

[Ron Petley]

If it is bent take it back.
Sometimes the belt glue seam makes a bit of a bump as it goes past the platten.
Take the belt off and and turn it on then move a pinceil close to the wheel, slowly inching in to the point that the pencil will just draw on the wheel. If the shaft is bent the pencil line will not be all around the whole wheel but just on part of it. Cheers Ron.

[george wilson]

The shaft being bent will not cause the wheel to wobble. Think about it. I will cause the wheel to run out of line. Only the wheel not being round,or being bent itself will cause it to wobble. I would either send it back,or in my case,turn a snug shaft to run it on(if possible,and true the wheel up in a lathe. If it has ball bearings in it,you may just have to send it back.

I had to true up the 10" cast aluminum wheel in my Wilton Square Wheel belt grinder. They now cost about $2500.00. Called the company,and told them I might expect the wheel to have to be trued on a cheap Asian grinder. Later I found out their grinder is made in Taiwan!!! Why the high cost? Running on the Wilton name,I guess. I fixed it myself,knowing they'd send me another out of true wheel.

LV should do better than that,from dealing with them.

I'm not familiar with this grinder,but molded plastic wheels can always possibly be out of round. If they are taken too hot from the mold,they can settle down out of round.

[Dave MacDonald]

Thanks for the tips. I initially discovered the wobble by placing a block next to the wheel, inching it forward as you said, and turning the wheel slowly by hand. It moved in and out of contact with the block on each revolution, but only by a very small amount.

The wheel is cast aluminum, not plastic, and mounts directly on the motor shaft; no ball bearings. I think, though, that if my motor were mounted crookedly, then the wheel would run without wobble but out of line. A bent shaft would in fact cause wobble, because its axis would be different than the axis of rotation. Right?

Any ideas how I would check the motor shaft itself? It's a furnace motor with a flat ground in the shaft for the set screw on the pulley (or in this case, wheel).

Thanks,
Dave

[george wilson]

Actually,I wasn't thinking clearly. IF the axle rotates with the wheel,and the frame has the bearings,the bent axle would cause wobble. I was imagining the axle was connected to the frame,and the bearings were in the wheel,as they are in my Wilton Square Wheel belt grinder.

[Marv Werner]

Dave,

I have a 1" belt sander that is belt driven off the motor shaft. Mine vibrated horribly. I found that the hole in the pulley that is on the motor was bigger than the motor shaft, not much, but enough to cause the pulley run off center or out of round. I ended up sleeving the pulley with a brass bushing to be a slip fit on the motor shaft. So, in my case, the pulley wasn't out of round, just off center.

In similar situations, I have had to remachine the V groove in a pulley to make concentric with the shaft hole.

Marv