Bandsaw noise issue

ldh · Post by **ldh** » Wed Nov 25, 2009 6:33 pm

I am just curious as to the number of members that have modified their band saws to use the double bearing fix I posted in PDF format a few months back. I personally have not had any noise problems with the saws I use.
ldh

robinson46176 · Post by **robinson46176** » Wed Nov 25, 2009 6:48 pm

What works for me is checking them now and then to be sure that they are not actually failing (as in about to fall apart) and ignoring the noise. I once had an old industrial 24" bandsaw that would drive half the cats out of the county. On the sawmill I used to have the engine noise covered any blade noise.
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My son had an old car years ago with a very annoying body noise at a given speed that he traced to its origin and determined it to be harmless. He cured it by turning the radio up...

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Now I think I read where someone mentioned having the front off of the bandsaw and turning it on.

That scares me and I am not afraid of anything...

That old 24" saw didn't have a guard on it at all when I got it so I made a wooden frame to retain the blade if it came off of the wheels. If you saw that huge blade come off and wad up a few times you would never take the cover off... I even had to replace part of the guard I made once. I used a 1" 3-TPI skip tooth blade on it and it was most unfriendly.

charlese · Post by **charlese** » Wed Nov 25, 2009 8:48 pm

After bandsawing another bunch of funny shaped play blocks, I took some time to listen to the saw.

When the saw is running at speed C+ and there is no sawing going on, the unit is as quiet as a church mouse way back in the hidden closet. (in other words - not much!)

When sawing through 5/4 maple there is a "not annoying" hum. I thought it was coming from the auto track roller, but after removing the cover and sawing while trying to pin point the hum - I could not find it. The hum never changed volume even when I pushed the wood rather than the correct pressure - just letting the blade do the cutting.

My conclusion is the saw blade and bearings/moving parts set up a resonance that is transfered through the saw. Could squealing noises also be resonance noises?

I'm now wondering if those folks with squealing bearings have remembered to use a sharpening stone to smooth the back of their blades. This not only smooths the back of the blade but will also round any sharp square edges.

Maybe rear blade smoothing and more bearing adjustments will help.

P.S. I checked the upper blade guide roller (bearing) is sitting very close to the back of the blade. (almost touching - maybe a couple of thousandths) in all positions from the table to 6" up. It looked like the lower blade guide roller is also this close.

JPG · Post by **JPG** » Wed Nov 25, 2009 9:16 pm

I did some sleuthing on the bandsaw today. I removed both upper and lower guide bearing and guide blocks. This allowed the blade to 'go where it wanted'. The only thing controllong its position was the guide bearings in the back. I determined the blade positioned itself about 1/8" in further than the lower guide bearing would position it. I concluded from this that the lower bearing does indeed position the blade on the lower side.

The upper<<<<Should be lower guide bearing is adjustable in /out, but only about 1/8". The distance from the casting where the bearing(and lockwasher) attach is about 1/16" closer to the blade guide blocks on the upper<<<<S/B Lower than the lower<<<<S/B Upper. I conclude from this that the intention was to nominally set the upper<<<<S/B Lower bracket in the center of its adjustment range.(1/16").

The bearings are 11mm wide and the blade falls about 2/3 the way from the back of the bearing(7.33mm). From this I conclude 7mm dual bearings are compatible(if the split lockwasher is NOT placed between the outer bearing and the casting). I conclude from this the lockwasher should be placed under the bolt head or not used at all. The jam nut on the upper bolt may not have enough threads with 14mm of bearing and a lock washer on the same bolt.

I reversed(flipped over) the bearings to provide 'new' contact points for the lower bearing and blade. Time will tell is squealing 'changes'.

charlese · Post by **charlese** » Wed Nov 25, 2009 11:19 pm

JPG40504 wrote: I determined the blade positioned itself about 1/8" in further than the lower guide bearing would position it. I concluded from this that the lower bearing does indeed position the blade on the lower side.

Yes, We agree on this positioning thing, provided there is pressure on the blade pushing it back into the bearing. However, there are more variables in the saw that determine blade tracking.

As noted in the post just above yours, my present 1/4" blade, with proper tension, just barely misses touching both the upper and lower guide bearings. Therefore, I could assume the auto track roller has positioned the blade. But we both know the alignment of the two wheels has something to do with the position of the blade.

The amount of blade pressure on the lower bearing is determined by the adjustment of the upper bearing.

JPG40504 wrote:The upper guide bearing is adjustable in /out, but only about 1/8". The distance from the casting where the bearing(and lockwasher) attach is about 1/16" closer to the blade guide blocks on the upper than the lower. I conclude from this that the intention was to nominally set the upper bracket in the center of its adjustment range.(1/16").

Have to disagree here! The saw manual (PDF from Post #4) clearly states the blade with proper tension should not be touching the upper guide bearing nor no more than 1/64" away from it. The guide post must be adjusted so this distance (less than 1/64", but not touching) is maintained through the entire range of of the post.

It is also recommended to check this positioning with each blade change.

JPG · Post by **JPG** » Thu Nov 26, 2009 2:04 am

charlese wrote:

Have to disagree here! The saw manual (PDF from Post #4) clearly states the blade with proper tension should not be touching the upper guide bearing nor no more than 1/64" away from it. The guide post must be adjusted so this distance (less than 1/64", but not touching) is maintained through the entire range of of the post.

It is also recommended to check this positioning with each blade change.

I was referring to the upper<<<<S/B Lower guide bracket sideways adjustment, not the blade to bearing clearance.

Whoops! I meant the LOWER guide bracket. The original post has been edited!

kd6vpe · Post by **kd6vpe** » Thu Nov 26, 2009 8:43 am

Hi I have not been up here much. I have a new job that is consuming most of my time now. This has been a very intersting read. Thank you for the PDF I do not have a manual for my bandsaw so this information is very helpful to me. I have a Magna bandsaw with the solid rollers that I just grease up when they start sqweaking. My question is does your upper blade guard have a lot of slop until it is locked in place? Mind does and near the middle of its travel when I lock it in place it is not super tight. I hope this makes sense. I am just wondering if it is worn out or not. Thank you again for this infomation I am going to go look closer a my bandsaw today to check things out. Happy Thanksgiving also.

JPG · Post by **JPG** » Thu Nov 26, 2009 11:01 am

kd6vpe wrote:Hi I have not been up here much. I have a new job that is consuming most of my time now. This has been a very intersting read. Thank you for the PDF I do not have a manual for my bandsaw so this information is very helpful to me. I have a Magna bandsaw with the solid rollers that I just grease up when they start sqweaking. My question is does your upper blade guard have a lot of slop until it is locked in place? Mind does and near the middle of its travel when I lock it in place it is not super tight. I hope this makes sense. I am just wondering if it is worn out or not. Thank you again for this infomation I am going to go look closer a my bandsaw today to check things out. Happy Thanksgiving also.

Looking at the upper blade guide mounting bracket,(the bracket at the top/inside the cover) where the adjustment screws(and jam nuts) are, is another screw(larger) toward the left edge of the bracket. This screw adjusts the clamp tension. The tension varying is probably caused by either/both wear or parts 'warp'. Increasing the tension should 'compensate' for the 'looseness'.

Happy Tday!:)

kd6vpe · Post by **kd6vpe** » Thu Nov 26, 2009 5:34 pm

Sweet,
Now I see what these three set screws can do. Thank you so much. Miraculusly my bandsaw seems to be pretty close to being set up right. The blade guard at the top position is alittle farther away from the back of the blade than when it is at to bottom position. One more question please. When I have the blade guard unlocked I there is alot of play front to back meaning the bearing can be moved by 1/4" until it is locked down then it is about a 65th away from the back of the blade is this normal movement?

BigSky · Post by **BigSky** » Thu Nov 26, 2009 5:56 pm

kd6vpe wrote:Sweet,
Now I see what these three set screws can do. Thank you so much. Miraculusly my bandsaw seems to be pretty close to being set up right. The blade guard at the top position is alittle farther away from the back of the blade than when it is at to bottom position. One more question please. When I have the blade guard unlocked I there is alot of play front to back meaning the bearing can be moved by 1/4" until it is locked down then it is about a 65th away from the back of the blade is this normal movement?

How far it can move back and forth depends on how the set screens with the jam nuts are set but when it is unlocked it is pretty loose. But when is it normally unlocked? When you plan to move it up and down then you lock it.

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