Buffer Vibrates with new wheels

[jfedullo]

I have a Baldor 1253 (3hp 3ph) buffer that I control with a variable frequency drive in order to get variable speed.

I just purchased all new 12" buffing wheels from Caswell and after I installed the sewn ones on one side (5) and the loose cotton ones (5) on the other, the machine vibrates like crazy. I tried raking them to get them more true (they have a bit of visable run out) visably and it is better, but it is still far from OK. I tired buffing at low speeds and you can feel the wheels pulse on the high spots. Raking helped a bit, but I can't seem to get the wheels trued up. Any suggestions? I can't spin much above 1000 RPM before it gets really violent and the machine used to be vibration free with the old (well worn) wheels.

Thanks,
-Joe

[baz]

Originally Posted by jfedullo

I have a Baldor 1253 (3hp 3ph) buffer that I control with a variable frequency drive in order to get variable speed.

I just purchased all new 12" buffing wheels from Caswell and after I installed the sewn ones on one side (5) and the loose cotton ones (5) on the other, the machine vibrates like crazy. I tried raking them to get them more true (they have a bit of visable run out) visably and it is better, but it is still far from OK. I tired buffing at low speeds and you can feel the wheels pulse on the high spots. Raking helped a bit, but I can't seem to get the wheels trued up. Any suggestions? I can't spin much above 1000 RPM before it gets really violent and the machine used to be vibration free with the old (well worn) wheels.

Thanks,
-Joe

does the wheel fit tight on the shaft if the hole is too big for the shaft you will have problems, if it is tight then i would think that the hole is not centered.
i have seen new wheels vibrate but after raking they are usually ok
maybe call caswell and explain your problem

[jfedullo]

The hole fits tight on the shaft and the nuts are tight against the aluminum arbors.

I think the hole is off center by a little bit on each buff. (I have 5 buffs stacked up on each side.) These are 12" buffs so if they are just a little off they shake a lot. It seems worse on the loose sew side than the spiral sewn side.

-Joe

[jfedullo]

Actually, maybe the buffs don't fit tight on the shaft...

The shaft measures 1.250" with my caliper and I ordered 1.25" holes so they are nominally the correct size, but I just loosened the nuts and checked and there is a little play. There is much more play on the loose sewn side than the spiral side. The spiral fits pretty close, but not really "tight" The loose sewn fits loose....

I'll post pictures tomorrow when my wife gets home with the camera.

I think you are on to something baz. Maybe if I try to hold the buffs centered while I tighten the nuts I will have better luck. Sounds like a project for tomorrow.

-Joe

[mpierich]

Originally Posted by jfedullo

Actually, maybe the buffs don't fit tight on the shaft...

The shaft measures 1.250" with my caliper and I ordered 1.25" holes so they are nominally the correct size, but I just loosened the nuts and checked and there is a little play. There is much more play on the loose sewn side than the spiral side. The spiral fits pretty close, but not really "tight" The loose sewn fits loose....

I'll post pictures tomorrow when my wife gets home with the camera.

I think you are on to something baz. Maybe if I try to hold the buffs centered while I tighten the nuts I will have better luck. Sounds like a project for tomorrow.

-Joe

Maybe some thinwall tubing as a spacer would help center them. I've also used tape wrapped around the shaft as a spacer. I generally just eyeball it myself, but then I usually don't stack wheels.

[jfedullo]

I was going to try 4 or more toothpicks circumfrentially around the shaft to help center it. I think that if I get the wheels centered than rake I might be in buisness. I'll try tonight and post back.

Thanks,
-Joe

[berndog]

I'd like to hear more about this variable frequency drive,,I've been curious and first time I've heard something on here.

[jfedullo]

I used the center of a toilet paper roll as a bushing of sorts. (I cut it longways and than trimmed it so it matched the ID perfectly.) On the spiral side the fit is now very tight. The loose sewn side is way better, but not as snug as the other side. I might wrap some tape around the OD of the roll. Anyaway after a rerake, I can get the machine to 3450 RPM, but it still vibrates. Just a vibration, not the violent shaking that happened before. I am going to keep playing with the bushing diameter and raking and I think it will be OK. A little disappointed that this was necessary, but hey I am back in buisness.

The VFD is controlling a 3 phase motor. It varies the voltage and frequency so that the speed varies. The one I am using takes 220V single phase as the input and puts out 220V 3 phase variable frequency. It works great, and you can slow the motor way down. The only regret I have is that I mounted it to the buffer itself and when the buffer started shaking violently I was worried it would kill the $400 VFD....

-Joe

[baz]

next time you order try ordering slightly smaller center hole , but you should still tell caswell about it if the center hole is really off so they can fix the problem

[jfedullo]

I replied to Caswell's satisfaction survey email with a link to this thread. They assured me that their holes are precision drilled, but offered buffs with a 1" center hole instead. I took them up on the offer so we will see if those do better.

I assume they will take a look at my old buffs and see that the holes are a little oversized and correct any process issues for future customers. So far they have been great to deal with.

-Joe