Bandsaw Vibration, why?

[John Kananis]

Hello all: I have a serious vibration issue with my 14" Ridgid bandsaw. I've changed the tires out with polyurethane tires, I've swapped out the rubber motor mounts with plywood (and shimmed it into position with a block of wood), I've checked the alignment of the wheels with a level (top to bottom at once), the wheels spin freely with no wobble when I hand-crank (even under tension), it happens with various sized blades (even new ones), the guides are where they're supposed to be and tightened. I do not allow tension on the blade when not in use. Everything I can see aligns properly and the blade doesn't rub anywhere its not supposed to.

The gosh darned thing was never perfect but now its gotten out of hand (progressively worse and worse).

What haven't I checked? Thank you.

[John Donofrio]

Have you checked the balance of the wheels? Some are balanced using weights, maybe they (or some) have fallen off.

[John Kananis]

Thank you for the quick reply. The wheels never had any weights for balance. I'm confident I can make my own weights by drilling into the wheels and adding some bolts through the holes but I wouldn't know how to balance these without a balancing machine. Any thoughts?

[Erik Loza]

Thank you for the quick reply. The wheels never had any weights for balance. I'm confident I can make my own weights by drilling into the wheels and adding some bolts through the holes but I wouldn't know how to balance these without a balancing machine. Any thoughts?

Do this: Take a sharpie marker and number the spokes of the wheel in sequential order. Without a blade on, spin the wheel a few times and watch where it lands. If it keeps landing on the same number, you've got an out of balance wheel. As far as re-balancing it? May not be cost effective on that particular machine but perhaps someone with more experience on the smaller saws could advise better than me. Best of luck with it.

Erik

[John Donofrio]

You could use the spin test. Blade off, mark a wheel then spin to see what it does). It should not stop in the same place every time and it should not come to a stop and then rotate in the opposite direction at all. If it does, I would suspect it's out of balance.

There's plenty of instruction/videos on the web. Check out some search hits from 'balance band saw wheels'.

[John Kananis]

Thank you folks. I found some resources on how to balance the wheels; I'll update the thread once I've tried this.

[Lee Schierer]

A wheel is unlikely to just get out of balance on its own. Before drilling any holes check for sawdust accumulation on the back side of the wheels. I would check the belt for condition and proper tension. You can eliminate the balance issue for the upper wheel by running the saw without a band. Then remove the belt and run just the motor. Try a different blade as a kink in a blade or bad weld will act like vibration.

[Judson Green]

You say you swapped out the rubber motor mounts with plywood, why? And is the drive belt tensioned right? And smooth - no lumps?

[Morey St. Denis]

Once you're confident everything has been checked at the level of a cursory overview of the mechanism, potential interference or alignment issues, it's time to drill down to the next level of detail work... You'll want to determine the frequency of that vibration, does it more closely match motor revolutions or rotations of the drive wheel? You'll need access to a dial micrometer that can check for shaft run-out and axial play in case any bearings may have become worn. If convenient to eventually dismount the wheels down to their hub, you could likely use an inexpensive conical balance tool that can be found in the lawnmower maintenance section of a hardware store (mower blade balance) to check for any gross wheel imbalances. I'm rather suspect of the removal of OE rubber damping bushings in favor of the described much higher modulus plywood mounting scheme... Rubber mounts are provided with the intended purpose that minute dynamic vibrations are passively damped and not get transmitted nor harmonically amplified by steel frame components. During any of the previous work did it ever become necessary to "persuade" certain stuck components with an impact blow or an inadvertent drop of the hardware? Sometimes bearing raceways can manifest internal peening due to prior impact damage. Kindly let us know something more about the frequency of that vibration...

[Rich Enders]

My problem was the drive belt. The original A980 from Rigid was worn, but still running smoothly. I replaced it with a new Gates and the vibration was terrible even after a long run in. When I went back to the original belt the vibration disappeared. I tried a link belt and it is better than the Gates, but not as good as the old A980.

I am not sure how to search directly on Sawmill Creek, but if you Google The "Quality" V-Belt thread you will come to a lengthy Sawmill Creek discussion of the belt situation on 14" band saws.

[John Kananis]

Thanks for the heads up, Rich. The original belt was replaced with a notched type (went to auto parts and sized it up).

Lee: No saw dust accumulation, belt and tires are relatively new. Also, happens with any blade I install.

[John Kananis]

You say you swapped out the rubber motor mounts with plywood, why? And is the drive belt tensioned right? And smooth - no lumps?

I've seen it done before on this model saw and it did help a bit.


Once you're confident everything has been checked at the level of a cursory overview of the mechanism, potential interference or alignment issues, it's time to drill down to the next level of detail work... You'll want to determine the frequency of that vibration, does it more closely match motor revolutions or rotations of the drive wheel? You'll need access to a dial micrometer that can check for shaft run-out and axial play in case any bearings may have become worn. If convenient to eventually dismount the wheels down to their hub, you could likely use an inexpensive conical balance tool that can be found in the lawnmower maintenance section of a hardware store (mower blade balance) to check for any gross wheel imbalances. I'm rather suspect of the removal of OE rubber damping bushings in favor of the described much higher modulus plywood mounting scheme... Rubber mounts are provided with the intended purpose that minute dynamic vibrations are passively damped and not get transmitted nor harmonically amplified by steel frame components. During any of the previous work did it ever become necessary to "persuade" certain stuck components with an impact blow or an inadvertent drop of the hardware? Sometimes bearing raceways can manifest internal peening due to prior impact damage. Kindly let us know something more about the frequency of that vibration...

Frequency of vibration (this is only a guestimate as I'm not using any type of calibration device aside from my ear) is about every three to four revolutions of the wheels. If I free-run the motor, it functions smoothly with no vibration. Same if I leave the bottom wheel attached with the belt.

I had a little time to play with the top wheel. A small relief cut (partially drilled a hole in the upper wheel - only took a little off at a time and didn't have to drill all the way through) helped put that one in balance (doesn't stop at the same point every time when you spin). After putting it all back together, I still had the vibration.

I had to run out before I could get to the bottom wheel - hopefully I don't get back too late this evening so I can play with it a little, otherwise tomorrow.

[Steve Peterson]

My bandsaw had some vibration issues after replacing the tires. The wheels were unbalanced enough that they would oscillate back and forth at the same spot after removing the blade. I solved it by adding foil tape around the hubs near the top. A couple of hubs probably have around 10 wraps of tape. It runs great now, but may need to be repeated when I replace the tires.

Whichever

Steve

[John Kananis]

My bandsaw had some vibration issues after replacing the tires. The wheels were unbalanced enough that they would oscillate back and forth at the same spot after removing the blade. I solved it by adding foil tape around the hubs near the top. A couple of hubs probably have around 10 wraps of tape. It runs great now, but may need to be repeated when I replace the tires.

Whichever

Steve

This makes sense. After I swapped out the tires, it seems that I noticed a little more vibration.

[Allan Speers]

1: Are your tires perfectly round? Supposedly this can be an issue on some lower-priced machines.


2: You said your wheels are coplanar, but did you check just in the middle, or on the far left & right, with the table removed? On some saws, the top wheel can get out of alignment where one side is further forward than the other. Some saws even have an adjustment for this, but I think you have to pull the wheel to get to it.


3: Last thought: Remove your blade, lay it on the floor fully opened, and check for any kinks or bends.

[Jerrimy Snook]

The original belt was replaced with a notched type (went to auto parts and sized it up). Automotive belts may not be as flexible as machinery belts. Have you reinstalled the original belt?

[Bill Orbine]

Look at where weld seams and kinks (there shouldn't be any) come across the blade guides.

[Eric Schmid]

The only adjustment I don't see mentioned is the plane of the motor shaft pulley and the lower wheel pulley. Are they co-planar? When they are out of alignment on my old Rockwell there is enough vibration in the belt to loosen the set screw on the motor pulley.

[Bruce Wrenn]

Have you checked to see if tires contain bumps. This could come from uneven stretching when installing. I remember seeing a tip where poster took a screw driver with round shank and lifted tire from wheel and made a couple passes around wheel to solve this problem. Joe Scharles did a tip on wrapping copper wire around spoke to balance band saw wheels.

[John Kananis]

You say you swapped out the rubber motor mounts with plywood, why? And is the drive belt tensioned right? And smooth - no lumps?

The ply improved things a bit and I have a wedge installed which holds the tension properly.


The original belt was replaced with a notched type (went to auto parts and sized it up). Automotive belts may not be as flexible as machinery belts. Have you reinstalled the original belt?

It was an improvement, the old belt had had it.


Look at where weld seams and kinks (there shouldn't be any) come across the blade guides.

I've tried a few different blades, from 1/4 to 1/2 inch.


The only adjustment I don't see mentioned is the plane of the motor shaft pulley and the lower wheel pulley. Are they co-planar? When they are out of alignment on my old Rockwell there is enough vibration in the belt to loosen the set screw on the motor pulley.

Pretty sure this is good but I will double check.


Have you checked to see if tires contain bumps. This could come from uneven stretching when installing. I remember seeing a tip where poster took a screw driver with round shank and lifted tire from wheel and made a couple passes around wheel to solve this problem. Joe Scharles did a tip on wrapping copper wire around spoke to balance band saw wheels.

I had to use the screwdriver trick when installing the new tires but on the outside to get the sides of the tires to seat properly. They are seated very well with no stretch on any one particular area.

I just want to say thank you for everyone's diligent participation in my thread - I really enjoy this forum.

[Andrew Hughes]

Okay Heres my blind guess from a thousand miles away,Does your saw have a metal stand that sits on a uneven floor?
Try lifting up on one of the corners.I had a bandsaw the base twisted if it wasn't shimmed right.

[Joe Bradshaw]

I put a piece of 3/4" ply between the saw base and the stand and bolted everything down. I also put on a link belt. This helped a lot.
Joe

[glenn bradley]

Look at where weld seams and kinks (there shouldn't be any) come across the blade guides.

I'm leaning this direction too. With the vibration appearing to be an oscillation problem (not occurring with every revolution) I start to suspect the blade. Although the top wheel could still be a problem, the fact that the problem has increased over time leads me away from that (unless it is bearing wear). Does the vibration occur with all blades?

[John Kananis]

Andrew: The frame of the saw is ok, it sits on a mobile base that I made years ago and everything is square.

Well, I had a couple of eureka moments but those moments turned into turds:

First, the allen screw securing the pulley to the lower wheel had loosened a bit and the motor and lower wheel pulley were not coplanar. I made the adjustment and all seemed well (visually). I also balanced the lower wheel (it wasn't that bad but I corrected the small inaccuracy). After putting it all together and powering up... SAME PROBLEM.

I'm at my wits end with this (almost - my OCD is the only thing preventing me from...)

Not sure where to go from here though. The thing that I can't wrap my head around is that the vibration does not occur every revolution!!?

[David L Morse]

thing that I can't wrap my head around is that the vibration does not occur every revolution!!?

Does the vibration frequency change if you change blade tension?

[Jim Dwight]

I'm not familiar with this bandsaw but if it takes a riser kit, is the joint in the frame tight? My old homemade bandsaw would flex it's wooden frame at higher blade tension resulting in a lower frequency oscillation.

[John Kananis]

Does the vibration frequency change if you change blade tension?

Just tried this, no.


I'm not familiar with this bandsaw but if it takes a riser kit, is the joint in the frame tight? My old homemade bandsaw would flex it's wooden frame at higher blade tension resulting in a lower frequency oscillation.

Tight as it gets.

[Erik Loza]

Throwing darts at the board: Could there be a crack or broken weld in one of the cast iron units or in the frame, that you haven't discovered yet?

Erik

[John Kananis]

Does the vibration frequency change if you change blade tension?


Throwing darts at the board: Could there be a crack or broken weld in one of the cast iron units or in the frame, that you haven't discovered yet?

Erik

Thank you for going outside the box on this but that dart missed its mark - just looked it over.

[Eric Schmid]

When you take all the covers off the saw and fire it up how do the moving parts look while in motion? You said the vibration goes away when the blade is off (driving only lower wheel) meaning you are only getting excessive vibration when there is load on the moving parts. I'd try looking closely at the effect of speed and load on the wheels, motor shaft, belt and pulleys. You've got the wheels balanced, but are they spinning true (as viewed from the side). Also you said you made two changes to the saw, belt and the mounting bushings. I'd probably start there.

[Myk Rian]

I balanced this wheel with paper clamps.
No need to number the spokes. Spin it. When it stops mark the bottom with a pencil, sharpie, etc.
Spin it a few more times. Mark it a few more times. Put weights on side opposite the marks.

[Allan Speers]

Re balancing aluminum wheels:

I always meant to try this on my old Delta, but never got around to it: You could probably make two circles out of MDF, and bolt + glue them to the existing wheels. Then balance them by drilling little bits off.

This way, you gain a lot of mass in the wheels, and also some vibration absorption.

- Might have to modify the wheel covers slightly, but it would be worth the trouble.

[Keith Westfall]

Sounds like you have covered almost everything possible!

If it only does it with the blade on, have you checked the upper and lower wheel bearings themselves? Under load they may be causing some problems if they are starting to go. No load they may spin free - under load it may be a different story...

Sorry, nothing else to offer!

[Dennis Aspö]

Regarding balancing weights, I used strong rare earth magnets as balancing weights, they're really on there. My bandsaw still has vibration, I think the lower wheel but I haven't bothered doing anything about it. My bandsaw also runs too fast, it's direct drive and the motor is probably too fast.

[Dennis Aspö]

Sounds like you have covered almost everything possible!

If it only does it with the blade on, have you checked the upper and lower wheel bearings themselves? Under load they may be causing some problems if they are starting to go. No load they may spin free - under load it may be a different story...

Sorry, nothing else to offer!

When bearings get old and the fat has hardened, they spin really free and easy, much easier than a new bearing. This was how it was on a motor I bought, once I replaced the grease it turned more like what I've come to expect, not nearly frictionless as it was before.

[John Kananis]

Well, I've inspected for cracks in the frame, balanced and aligned everything, tried several blades, different tension, removed and etc.

Keith: The bearings really are the only thing left. I don't really know how to replace these or where to find a set. Any guidance?

[Allan Speers]

Say,

Maybe the saw is fine, and it's YOU that's shaking. Have you been drinking too much coffee lately?

[Keith Westfall]

I don't really know how to replace these or where to find a set. Any guidance?

If you can get them out, find a bearing retailer (google your area) and take them there. They will be able to replace them.

[John Kananis]

I think I've identified the problem: The lower wheel pulley is ever so slightly bent - this may be a recent development but the machining on this pulley is outright horrendous. The shaft bore is out of center by 1/16" and I wonder if its even a straight bore.

I'm going to run out to the auto parts store (soon I hope) and pick up an 'upgrade'.

The only components left that could be suspect are the lower wheel bearing and the shaft itself (highly unlikely but I've seen nuttier things out of China). The bearing 'sounds' ok but I don't have a stethoscope-like device to really listen to it. If the pulley venture doesn't work out, I'll work out how to r/r the bearing - I may get luck and its not pressed in.

I'll update when I have the solution.

EDIT: Correction on an earlier statement - not sure how I made this error but - the vibration is present when not under load and only the lower wheel is driven (the motor on its own is whisper smooth). Apologies for making it a bit difficult to assist me.

[Erik Manchester]

Good luck. A quality cast iron pulley is a must, those cheap alloy pulleys are easily damaged.

[Keith Westfall]

If you can get close to the bearing with a steel rod (without getting caught in the pulley!), and put the other end up to your ear (I use the little piece of the ear right above the lobe) it will act as an excellent stethoscope. Maybe not as good as a real one, but very useful in lots of situations.

Any small rod, ready rod, screwdriver will do.

[Bradley Boyle]

Since this problem was not evident until recently and you have already checked or replaced the drive belt, tires and blade, I would have to believe that your problem is with the bearings or castings. I would remove both sets of bearings (both upper and lower) and throughly inspect them. If any of them do not turn smoothly, replace all four of them. If the bearings are in good order, then meticulously check the castings for cracks. Be certain to have the blade fully tensioned when you perform this inspection. Small cracks may not be visible when the tension is off.

[John Kananis]

Figured I should update for those following along. I ordered a cast iron pulley and a set of bearings for the lower wheel - just finished installing.

The 'overall' performance of the saw has improved (the one bearing was definitely starting to go and the pulley was just a joke.

However, I still have that odd pulsation every few revolutions (lower pulley connected to the motor.

I inspected the bore shaft and it looks good (no dial indicator but to make this much ruckus, there would need to be a visible defect when held against a straight-edge, no?

At this point (since EVERYTHING else has been replaced), I can only assume its the bearings in the motor but the thing just purrs when not under load (not attached to the lower wheel pulley via the belt).

Any thoughts?

[John Kananis]

Last update - saw works much better.

My brother-in-law happened to have a 1hp Dayton sitting around which he let me have for $100 (fair deal). Wired it up for 115 volts, reversed the rotation; we shoot, we score. For all the time I've invested in this machine, it works much better overall. I must comment to anyone whom owns this saw, the greatest improvement to the overall performance (by far) was to install a ply base between saw and base - sheet material used at the factory is far too thin, combine with the open base and this makes for a very 'shaky' environment.

[Larry Frank]

Glad to hear you got it fixed. And very nice to post a final solution. You now have the experience to fix all things bandsaw.

The last thing you have to do is make sawdust.