Blade Vibration Issues

[highleadtimber16]

Was cutting some 1X4 WRC today and my blade started leaving marks on the wood. I could see my blade guide arm was vibrating. Checked it and it's solid as a rock. Called Wood-Mizer and we can't figure it out. Checked bearings, wheels, belts, the whole works. The vibration is less if I have the arm fully extended outwards. Anyone have any ideas!? Thanks! 

[mikeb1079]

i've seen it before where one or two teeth are out of set so they dig into the cant slightly further, leave a mark and cause vibration.  are these resharps?

[Magicman]

Check the groves in the blade roller guides.  I have seen bark wedge itself in a groove and cause vibration.

[drobertson]

Yes maybe, the center guide on top of the band, between the wheels, 1/16" clearance, the other, even though you said you checked it, I would again check the guide wheels on the moveable side of the blade guides, all the way out, there is not much hanging out, in around 6 to 8" there is quite a  bit of hang going on, just a thought,
15/16" and an 1-1/8 open end, will get to it. Both require just a tad bit of patience to bring in. Might not be it at all. could be a blade, or blade clearance on the bottom guides. I hate it when there is an issue, they can be found, just a task to be done.

[highleadtimber16]

Was using a brand new blade then switched to a resharpened blade, then another. Rollers are clean as a whistle. I've checked everything I can think of. Wood-Mizer suggested the possibility of the outside band wheel being warped... Hoping that isn't it. Mill only has 725 hours on it.

[highleadtimber16]

Yes maybe, the center guide on top of the band, between the wheels, 1/16" clearance, the other, even though you said you checked it, I would again check the guide wheels on the moveable side of the blade guides, all the way out, there is not much hanging out, in around 6 to 8" there is quite a  bit of hang going on, just a thought,
15/16" and an 1-1/8 open end, will get to it. Both require just a tad bit of patience to bring in. Might not be it at all. could be a blade, or blade clearance on the bottom guides. I hate it when there is an issue, they can be found, just a task to be done.

I'll check this tomorrow morning to just to make sure. I'm thinking possibly there isn't enough down pressure on the blade when the arm is in, but it seems the same as it has always been.

[pineywoods]

Sounds very much like a wad of compacted sawdust/rosin under a bandwheel belt. Pull off the blade, then remove both belts and look in the bandwheel grooves. Hope you aren't one of those who put B56 belts on your bandwheels... :

[highleadtimber16]

pineywoods, that was the first thing I checked. They're clean and I clean them every time I change my blade. I checked all the easy stuff. I think.....   :

[wetdog]

Check your drive belt for a chunk of missing rubber.

[highleadtimber16]

Check your drive belt for a chunk of missing rubber.

Done.....  :-\

[drobertson]

I had the wobble like I think you mentioned a while back, then noticed the blade guide drifting in while sawing, the cam bolts that align the v-wheels for the blade guide were just a tad off. Mine needed a tweak counter clockwise, I mean a tweak, and all is good again, weird, just machines I guess. Might check it and if nothing else give all the nuts a good snug,

[highleadtimber16]

I'll definitely check this. Thanks for all the help you guys. 

[backwoods sawyer]

Something you can try is to open it up and hand spin it, when you feel something stop and see it you can find it that way.
Since all the groves are clean take a close look at the guides to see if one has a flat spot. Vibrations are usualy fairly easy to track down but several things can cause them.

[Brucer]

You will sometimes see this sort of thing when your blade starts to resonate.

The blade has a natural frequency (just as a guitar string does). The natural frequency is affected by the blade tension, the distance between the blade guide rollers, the temperature of the blade, and the width and thickness of your blade. If you impose some external vibration on the blade that is within about 20% of the natural frequency, the blade will resonate and you will often see marks showing up on the wood that wouldn't normally be there.

External vibration can be caused by stuff caught under a band wheel, buildup on a blade guide roller, a failing bearing, the speed of the blade, and even the tooth spacing.

Some things will help to damp out the vibrations, such as the species of wood, how green it is, and whether or not you are using blade lube.

The mast on your mill can also contribute to resonance problems. The height of the blade above the deck, the pressure you're applying to the cut, and the amount of weight the head is carrying (e.g., fuel and water level).

As you can see, there are a lot of variables. They all have to come together in one particular combination to cause resonance.

The best way to test of this is to make a radical change to one or more of the variables. It doesn't matter too much which way you change them. Try changing your blade tension, jack up your blade coolant flow (or slow it down), or change the carriage speed.

[backwoods sawyer]

since the guide arm position seems to have an effect, a good place to start would be removing the guide on the adjustable side. resting the tip of a flat tip screw drive so it will bounce on the saw at a low angle while pointed in the dirction the saw is turning will tell you how much vibration you have and if there is a change.

You changed the saw so that eliminats a cracked saw.

[highleadtimber16]

Ok, it seems the vibration has lessened   ??? It always starts after the second bed rail and ends before the last stationary rail. It only really vibrates and leaves noticeable marks when edging. This whole thing is really odd. I checked the bolts on the blade guide arm. They are TIGHT! Any thoughts? 

[drobertson]

Only tighten the blade to the max? I mean the max,  I saw some oscillations again today, maxed the tension and it went away, not sure of your situation,  I still believe blade and guide clearance are important factors, as is the particular band being used. 

[customsawyer]

See if there is a piece of bark or some such in the grooves of the drive belt pulley.

[petefrom bearswamp]

Sawmill gremlins at work.
Hope you come up with a solution soon.
Pineywoods I tried the b56 belts years ago and quickly gave up on them.

[Ga Mtn Man]

...I tried the b56 belts years ago and quickly gave up on them.

What issues did you have with the B56's?

[highleadtimber16]

I checked the drive belt. It has cracks. Wood-Mizer said this is fine as long as there isn't big chunks missing. It's odd how the vibration starts, then stops at certain places.

[Peter Drouin]

I checked the drive belt. It has cracks. Wood-Mizer said this is fine as long as there isn't big chunks missing. It's odd how the vibration starts, then stops at certain places.

I would change the drive belt. The B57s too

[highleadtimber16]

Peter, I agree. I will order a new one tomorrow. The B57s are brand new as I just did a service on the mill 10 hours ago.

[drobertson]

You never mentioned if the moveable side of the blade guide was right,  If it is vibrating on and off, it really sound like an issue other than belts,  New belts are good, but really necessary? 

[highleadtimber16]

drobertson, I checked the bolts and they're tight. The arm seems pretty *DanG tight. Like I said, it vibrates after the second bed rail and stops around the last rail. The guard that is held on by two welds seems to vibrate a lot. I thought about cutting it off. But it's probably there for a good reason and I don't want to start butchering my mill  :-\