Pulley of a bandsaw

[Susumu Mori]

Hi all,

After trying to hunt down the source of the noise and vibration of my bandsaw, I found that the pulley and the bottom wheel are not aligned by about 3-4 mm. I don't want to move the wheel because it is now nicely aligned to the upper wheel. So, I guess I have to move the pulley but I'm stuck; the pulley doesn't move.

The pulley has a tiny set screw. I can't believe that this heavy duty pulley is secured only by this tiny screw. The diagram seems to show there are two set screws in tandem but I can see only one in place. Oddly, this set screw was very loose to begin with.

Anyway, I removed the set screw but the pulley stays.
I wonder if somebody can explain how pulleys are secured and moved in general. I certainly do not want to yank it without knowing what I'm supposed to do.

Your help would be appreciated.

[Matt Day]

A picture would help, but obviously you need to make sure that all set screws are removed.

The pulley is likely mounted on a shaft. On that shaft there is a flat area (called a keyway) which aligns with the set screw, and the set screw tightens a key that locks the pulley in place.

Assuming some screws are all removed, likely the pulley is somewhat frozen on the shaft.you will likely need a three jaw polar to remove/unlock the pulley. You might be able to get a loaner tool from an auto parts store, or they are pretty cheap at Harbor freight.

[glenn bradley]

Many such machines have a set screw with another set screw driven in on top of it to lock it in place. If you have removed one, there may be another still in place in the same hole.

[Susumu Mori]

Thanks Matt and Glenn,

I assume the both screws have the same hex size. I tried but couldn't engage the hex driver to find the second screw.
I attached the pics of the pulley. It seems to have some kind of mechanism at the center because what I see in the middle doesn't look like the shaft of the motor (yellow arrow). There is a square window (red arrow) and there is something inside the window. It almost looks like that the hub of the pulley can be removed, but not sure.
Presentation1.jpg

[Matt Day]

The red arrow is the keyway I descibed. Do a google image search for "keyway shaft pulley" and you'll see some examples of it apart. That should help you understand what's going on.

The yellow arow is the shaft, and the center is where the bearing puller centers itself.

You didn't remove the set screw if the belt never came off. Remove the belt and you'll see a hole, or two.

[Susumu Mori]

Thanks Matt,

That makes a sense. I could finally adjust the pulley position, but now I found that the motor and the wheel are not co-planer!!
As a matter of fact, no matter where I adjust the pulley position, it goes back to the inner most position while using, because the motor shaft is tilted upward (or the wheel shaft is tilted down). The small set screw is not strong enough to keep the pulley in place.

Because the upper and lower are aligned quite well, I assume that I need to adjust the motor tilt, but there seems no way to adjust it.

I wonder how the co-planer is adjusted between the motor and the wheel.

[Matt Day]

I'm not sure how your motor is installed, but can you simply shim the motor mounts (bolts that hold the motor in place)?

i wouldn't think that set screw would need a ton of pressure to keep the pulley in place. When you check the pulley and wheel for coplanar-ity (is that a word?), I would think you would see if the motor was tilted. Do you?

You could probably use a stop collar of some sort on the back of the pulley to keep it from moving in.

[Susumu Mori]

Thanks Matt,

I shimmed the bottom of the motor, correcting the sagging.
Now the two shafts are more parallel and the pulley stays at the coplanar position.
Thank you so much.

As for the noise/vibration, I noticed the initial shaking of the saw when the motor starts was noticeably reduced but once the saw is up and running, there is not much difference. Nickels are at least standing still. It is interesting to see how the quiet running motor (when motor alone is running) and the smooth and balanced wheel can make this much noise once they are connected. I think the most of them are from the v-belt slapping the pulley and the wheel grooves.

Oh well, I guess I played around enough and it is time to make more saw dust.

thank you for the help anyway. I think these adjustments were good for the longevity of the saw.

[Matt Day]

Glad I could help.

You mention the v belt slapping - is your belt tension high enough?

[Myk Rian]

Glad I could help.

You mention the v belt slapping - is your belt tension high enough?

But not too tight, or you'll be wearing bearings out.

[Frank Pratt]

I had the same problem with my Rikon 10-325. The lower wheel was badly out of line with the upper wheel & by the time I got that sorted out, the motor pulley was not coplanar, to the point where is shredded the belt. I used shims on the motor mounts to get it right, but it took a lot of fiddling.