Bandsaw noise issue

[JPG]

The blade barely contacts the bearing so sometimes it spins and sometimes it doesn’t, which must be the correct setting since there is no in-out adjustment of the guide bearings. Since the upper and lower bearing can be swapped with the noise source remaining on the bottom we know the problem is not due to the bearing itself, but a function of the bearing position and its contact with the blade.

The photo shows--without any significant parallax error--that even with the adjustment all the way to the right the blade is still probably 3/16” from the center of the bearing.

The noise is due to a combination of the bearing rotation and the back of the blade moving across the bearing face. I suspect the blade crosses the bearing face at a very slight angle which causes the squalling noise.

If the photo were 'dead on with no parallelax' the side of the blade would Not be visable. If the shadow is caused by the camera flash, the shadow would be either not visible or very near the blade(flash not aligned with the lens).

10-4 everything else!:)

[dusty]

If the photo were 'dead on with no parallelax' the side of the blade would Not be visable. If the shadow is caused by the camera flash, the shadow would be either not visible or very near the blade(flash not aligned with the lens).

10-4 everything else!:)

mindpilot and jpg

If this discussion about parallax is regarding my photo of the upper guide bearing - the blade is tracking in the gap between the bearings.

If it does not seem that way, it is an optical illusion (parallax or no). Blame it on the photographer.

[charlese]

Let me take a different approach to the LOWER BEARING SQUEAL.

I really believe it is possible that the problem of lower bearing squeal is not the fault of that bearing, or its mount, at all. It is possibly caused by mis-adjustment of the upper bearing. Remembering when I got my brand new bandsaw, it took me a whole afternoon to adjust the upper arm and and bearing so the bearing was slightly away from the back of a blade and not more than 1/64th inch away from the blade in all vertical positions. This adjustment of factory settings was needed, if the saw was to be set up according to the manual.

I've never had a squeal.

[dusty]

I am curious how you chose to adjust it differently. What are you doing differently? The lower bearing is not adjustable front to rear. If the blade does not touch the lower bearing the blade is unrestrained approaching the lower wheel(when not cutting).

I have done nothing to the lower bearing except put in a pair of 627Z bearings. Yes, they are 22mm.

The bearing alteration should not affect in/out(assuming you are using 22mm bearings). Is it possible the groove between the bearings increases the bearing/blade spacing enough for the blade to clear the bearings? Is it possible your upper wheel is canted front to rear similar to the top bottom cant? (blade down side(open throat side) toward the tooth side of the blade?)

Yes, the groove must increase the spacing between the contact surface on the bearing and the back of the blade existed before the bearing change.

The upper wheel is canted as it should be. If it was not, the blade would tend to move to the outer side of the wheel and possible come off.

I truely believe the lower bearing is intended to serve two functions. 1) backup the blade while cutting. 2)Position the blade as it moves toward the lower wheel.

You are absolutely correct. Remember though that this function is aided by the cool blocks. It is not just the bearing.


WHOOPS! I assumed you also changed the lower bearings. Didja? What width bearings are you using?

Yes, all of the bearings (6) in my bandsaw are now 627Zs.

Of course there are the wheel bearings which I have not changed. This sorta worries me]

[dusty]

Let me take a different approach to the LOWER BEARING SQUEAL.

I really believe it is possible that the problem of lower bearing squeal is not the fault of that bearing, or its mount, at all. It is possibly caused by mis-adjustment of the upper bearing. Remembering when I got my brand new bandsaw, it took me a whole afternoon to adjust the upper arm and and bearing so the bearing was slightly away from the back of a blade and not more than 1/64th inch away from the blade in all vertical positions. This adjustment of factory settings was needed, if the saw was to be set up according to the manual.

I've never had a squeal.

I agree with this - especially because I don't believe the bearings would fail as frequently as they had seemed to be failing. It the past, I was changing the bearing sets about once a year due to the squeal.

I have all of the old bearings other than those that have been re-purposed.

Unless I start building wooden cars and trucks, I may have a lifetime supply.

[JPG]

Of course there are the wheel bearings which I have not changed. This sorta worries me]

Thank You for the multiple answers the multiple questions!

I have come around to believe the squealing is caused by the back of the blade 'sliding' on the face of the lower bearing. It occurs when the blade is 'gently' against the bearing.

[dusty]

Thank You for the multiple answers the multiple questions!

I have come around to believe the squealing is caused by the back of the blade 'sliding' on the face of the lower bearing. It occurs when the blade is 'gently' against the bearing.

I AGREE but have one question. Why does changing bearings "almost always" eliminate the squeal for some period of time after the exchange???

[judaspre1982]

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[billmayo]

Maybe the bearing surface gets small groves in the face of the bearing causing more vibration between beaing and blade. Sort of like a cars rotors or drums for the brakes. When they get uneven wear they start to squeal.----Dave

I find that the bandsaw roller bearings are a common motor grade bearings that fails quite often. I have even changed a few of the roller bearing bandsaws back to the original solid bushing rollers that only need lubrication every year or so. I have since gone to a higher grade (more precision) double bearings that seems to work OK.

Has anyone figured out the RPM that these roller bearings turn when the bandsaw blade is againest them. Maybe, the RPM exceeds the rated RPM for this small bearing which will still work for a while when replaced.

Since the roller bearings Shopsmith used is shielded, a small amount of very fine sawdust may be getting into both sides of the bottom bearing is causing the problem. With the double bearing, only one side of each shielded bearing is exposed to the sawdust.

[JPG]

I AGREE but have one question. Why does changing bearings "almost always" eliminate the squeal for some period of time after the exchange???

The surface conditions causing the squeal are altered until they can be 'rebuilt'.