Bandsaw Vibration

rcarmac

Robert
Corporate Member
The vibration on my Jet 18” bandsaw keeps getting worse. I have tried changing out the blade with some new blades I just received from woodcraft bands. The base is level and solid. I don’t know if the wheels are out of balance or maybe I need to replace the tires.
 

Brian Patterson

New User
Bstrom
Clean tires will make a difference as well as blade tension. Beyond that, bearings and adjusting the ride of the blade on the the right are about all there is to these tools. Got some pix?
 

rcarmac

Robert
Corporate Member
I felt that belt and it didn’t have any cracks and was tight. What should i be looking for in the belt
 

Roy G

Roy
Senior User
Have you tried running it without a blade on it? Maybe a wheel or motor bearing is bad. Do you feel anything when you spin the upper wheel without the blade on it?

Roy G
 

bob vaughan

Bob Vaughan
Senior User
A real outside chance is that sawdust has collected on the inside of the wheel (if it is a solid wheel and not spoked). I've seen this rare condition where sawdust builds up to a point and then a big clump falls off thus creating an imbalance.
 

rcarmac

Robert
Corporate Member
Have you tried running it without a blade on it? Maybe a wheel or motor bearing is bad. Do you feel anything when you spin the upper wheel without the blade on it?

Roy G
Haven’t tried that yet but I will
 

junquecol

Bruce
User
Check to make sure the tires aren't bunching up under the blade. If they are loose, they will bunch up, creating a lump under the blade
 

Brian Patterson

New User
Bstrom
Wow - even I didn’t know about these potential trouble areas. Almost glad you’re having an issue with yours - not really but this is good info to have.
 

patlaw

Mike
Corporate Member
Anyone know how to upload a video
Upload the video to YouTube or another hosting service and post the link here. The allowed hosting services are shown in the Insert --> Media tab on the posting menu. I don't know if a video can be uploaded to the NCWW server. I've never tried it.

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junquecol

Bruce
User
Check the clearance on the guide blocks / bearings. The weld could be causing a slight stopage each time it passes between them. If the weld is rough, a couple swipes with a Dremel will take care of that. Because it's happening with more than one blade, I suspect it's in the wheels. Take the blade off, with cord disconnected, fashion some kind of pointer that just clears the wheel. Turn by hand and see if clearance changes. Do both upper and lower
 
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Volksdad

Glen
Corporate Member
I have a much cheaper ridgid bandsaw, and it used to dance all over the place. I did a few things that really changed the way that it runs.

I added a 2”thick wooden base to the stand. This added mass. I changed the belt to a segmented one. I balanced the upper wheel with lead wheel weights, and changed the tires to inexpensive urethane ones that I bought from amazon. It’s like a brand new saw now.
 

tvrgeek

tvrgeek
User
All good comments Just want to expand on belts.
A new belt frequently does wonders. I don't fall for the link adjustable belt stuff, but a good Gates notched belt can do wonders, of if a multi-groove, just a new one. Older cheap belts will cause issues, and I can assure you Jet used the cheapest belt they could buy. A belt is like anything rubber Life is less than 7 years. Maintenance item. It is not uncommon for woodworking tools to have sheaves smaller than the belt manufacturer spec. That makes an older belt even worse.
 

Oka

Casey
Corporate Member
I would pull the blade, then the belts on the blade wheels 1st. Then check both wheels with a dial indicator. I would check the rotation drift and the side drift. If they are within tolerance then replace the belts. Not sure what the tolerance is for your machine. But, my gut tells me 2-5 thousandths would be ok. While it is apart check carefully the bearings and their condition.
One trick you can do if your phone has the close up camera feature is to video in close up then put on your computer to carefully analyze.
 

marinosr

Richard
Senior User
You can use frequency analysis to isolate the problem. The sound is a really low-frequency problem, sounds like about five thumps per second, or 5 Hz. Now, what part of your machine cycles at around 5 Hz? Your wheels move faster than that, about., 35 Hz, so you know that it is not a sound made by the wheel every time it spins around. Assuming a speed of around 3000 feet per minute for your band saw blade, which is typical, and a blade length of 96", that means your blade makes (3000*12)/(96*60)= 6.25 complete rotations per second, which is kinda close to my guess of 5 thumps per second. So I would first suspect it's an issue associated with the blade making a thump every time it makes one turn. Maybe the blades aren't tensioned well and the weld is hitting something as it goes around? (This is a very amateur attempt at frequency analysis but skilled industrial mechanics do this sort of thing all the time for very expensive machines... Put a mic on it, calculate the frequency of the troublesome noise, find which part in the machine spins at that frequency (or a harmonic of it), and bingo problem identified.)
 

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