Shopsmith bandsaw problem

[nuhobby]

Hi,

Many past postings concern the bandsaw so I thought I'd chip in my experiences from the last week, where I've been working on a friend's 30-yr-old bandsaw, and in the process by comparison decided to improve my own bandsaw noise.

(1.) Wheel roundness. All SS wheels, old and new, have the grooves for the rubber belts which are machined 'true' to the wheel's rotation on the bearings. Older wheels additionally have an apparent "truing machining operation" to take away the lateral-runout (side to side visible wobble) in the rough metal casting outlines. Newer wheels, instead of having the castings evened-out everywhere, can have some visible wobble in the metal material on either side of the true-running rubber tire, but they have CNC-drilled material removal on the backsides of the metal rims, for mass balancing.

(2.) Upper wheel bearing play, including fiber washer and retaining clip. I was not sure if it's good for the fiber washer to press things so tightly that the retaining-clip ends up rotating (with friction) on the axle shaft. I had an upper wheel which had some 'knocking' noise that you would have thought was related to the 'weld' on the blade hitting somewhere once per travel. But actually it was the upper-wheel, in a state of not tracking well, hunting back and forth on its shaft slightly (no more than 1/16"). Turns out this wheel/arm was not 'canted' as intended, where the upper wheel is meant to have its top edge slightly further away from the plastic bandsaw cover than the bottom edge is, for good blade tracking. When I did the arm-bending alignment for proper wheel canting, then finally this wheel ran quietly even with a small amount of play remaining between fiber-washer and retaining-clip.

(3.) Autotracking bearing (the double bearing near the tension adjuster). This pair of bearings (where the groove retains the blade) needs to be *exactly* running in-line and parallel with the blade, in order to be quiet. If it's not well-aligned, the unequally-driven halves of this pair can be very noisy. This bearing alignment will likely need to change for each different style of blade that is used & tensioned.

(4.) Other bearings -- many other posts cover the adjustments of these very well.

[pastor]

"If you've got a manual, look up "Adjusting the Blade Rollers." Start with the auto-track roller, then the lower blade guide roller, then the upper blade guide roller in that order. If you'r missing the manual, I'll be glad to post the procedure here. "

Did you ever post this? My problem is getting the saw to cut straight and I'm wondering if the guide rollers might be the problem. Are they the rollers that sit right behind the blade? Is the blade supposed to be touching them? Thanks.

[JPG]

"If you've got a manual, look up "Adjusting the Blade Rollers." Start with the auto-track roller, then the lower blade guide roller, then the upper blade guide roller in that order. If you'r missing the manual, I'll be glad to post the procedure here. "

Did you ever post this? My problem is getting the saw to cut straight and I'm wondering if the guide rollers might be the problem. Are they the rollers that sit right behind the blade? Is the blade supposed to be touching them? Thanks.

Nick is not likely to respond. Although I do not presume to be his 'equal', I will attempt to be an adequate substitute.

1) Everything that follows assumes a straight(not bent) blade properly mounted and tensioned and the table removed for access. The blade guides are backed away from the blade.

2) Auto track Bearing - Loosen the mounting bracket bolt and slide the bracket sideways(in and out of the 'throat') so as to center the bearing split(there are two bearings side by side) directly behind the blade. Make sure the bearings do not get canted while doing so. The sides of the bearings should be parallel(vertical) with the sides of the blade. Retighten the mounting bolt.

3) Lower blade guide bearing - Loosen the bolt which holds the blade guide/bearing assembly and also move it in and out so as to center the bearing behind the blade. Retighten the mounting bolt.

4) Upper blade guide bearing(centering) - Loosen the two guide post bracket mounting bolts and pivot the guide post so as to center the bearing behind the blade. Retighten the mounting bolts.

5) Upper blade guide bearing(blade backup clearance) - This one is exasperating to perform! Much trial and re-adjustment will be required. The intent is to adjust the guide post so as to provide a constant clearance between the bearing and the blade throughout the height positioning range of the guide post.

Loosen the two jam nuts on the guide post adjustment screws(not the bracket mounting bolts). These screws allow the guide post to be adjusted parallel(vertical) to the back of the blade. They are not tightened, but are snugged up only.

By retracting the upper screw and advancing the lower screw the bearing(at the lower end) is moved away from the blade. Since the guide post is pivoting near the top, it will not alter(as much) the distance from the blade to the bearing when the guide post is raised. Reversing the screw adjustments will reverse the result.

Retracting or advancing both upper and lower screws the same amount in the same direction, changes the clearance between the bearing and the back of the blade. Unfortunately this also changes the tension of the guide height lock. The lock tension is adjusted by screw located towards the back of the guide post mounting bracket.

The intended goal is to provide more than zero clearance and less that 1/64" clearance between the bearing and the back of the blade at all height positions of the guide post(after it is locked).

I suggest getting the top and bottom clearance equal first, then adjusting the amount of clearance and tension second. Don't forget to tighten the jam nuts. While holding the position of the bolts, tighten the jam nuts.

Tain't easy Magee! Good Luck!

[pastor]

Thanks. I will give this a try. Hopefully when I'm looking at the bandsaw, all of this will make sense to me. I really appreciate it.

[mindpilot]

From day one my bandsaw let out this annoying squeal seemingly at random. I finally got around to spending some time isolating the cause, and sure enough it is the lower guide bearing. I even removed it (of course it says "made in China") and soaked it some oil. Didn't help a bit.

It looks like SS got a batch of bad bearings. But the upper and lower bearing carry the same part number, wonder why we are all experiencing the problem with the lower bearing?

I'm going to try swapping the upper and lower bearing to see if the problem moves with the bearing or maybe it's more complicated that just a bad bearing.

On edit: It's not the bearing--after swapping top for bottom, the noise is still there and it can still be quieted by stopping the lower bearing. The problem appears to be that it is impossible (without some serious modification) to adjust the lower mount so the blade centers on the lower bearing. In the picture below, I have hit the limit of the adjustment and the blade is nowhere near the center of the bearing. I did try replacing the lockwasher with a thin shim which actually seemed to reduce the noise, but the bearing outer housing ran uncomfortably close to the mount. The only other option would be to elongate the adjustment opening in the mount, but there is very little material there and removing enough to facilitate the adjustment would certainly weaken the mount. I am begining the think the best fix is to drill another mounting hole in the main housing. Does anyone else have this issue?

[dusty]

From day one my bandsaw let out this annoying squeal seemingly at random. I finally got around to spending some time isolating the cause, and sure enough it is the lower guide bearing. I even removed it (of course it says "made in China") and soaked it some oil. Didn't help a bit.

It looks like SS got a batch of bad bearings. But the upper and lower bearing carry the same part number, wonder why we are all experiencing the problem with the lower bearing?

I'm going to try swapping the upper and lower bearing to see if the problem moves with the bearing or maybe it's more complicated that just a bad bearing.

Many have experienced what you describe, including myself.

After simply changing bearings three or four different times and each time eliminating the squeal for a few months (maybe longer), I did a complete tear down and rebuild. This time I seem to be getting better performance. It has been almost two years on the last set of bearings.

I cannot confirm that it has always been the lower bearing but if that is the case it might be because that particular bearing is almost always caked with sawdust. The other bearings are positioned such that they are not so exposed.

[paulmcohen]

Look at the attached bearing modification plans, after doing this the noise goes away. You may need to elongate the mounting hole (several of us did) until the bearing rides in the middle. Elongate very, very slowly but even with little metal the part is strong enough to work.

The modification replaces the single bearing with two and the blade rides down the middle.

Purchase high quality sealed bearings, they are only a few cents more than lower quality ones.

After doing these modifications everything about the bandsaw works better.

[courtney49]

A couple years ago I upgraded (Changed) my bandsaw to the Urethane tires. I am light user of the bandsaw but recently I changed the blade for some resawing (1/2 inch blade) and thought I had made all the appropriate adjustments before starting it up.

I had a very simple sawing job on a piece of 1/4 plywood. That's when things started flying apart. Upon inspection it became evident that the Urethane tires came off the wheel. I am still not certain I why thing came apart but Urethane tire was not very tight on the wheel at all.

Do the Urethane tire have a tendency to stretch-out? If so, how long do they last usually?

Any other comments are welcome.

Courtney49

[moose]

Courtney: If you research this in the forum, you will discover you are not the only one to have this problem. At one time, SS shipped out a bunch of urethane tires that were too big. Evidently, you are in receipt of this error. SS will make it right if you just call them. The urethane tires should last forever.

Ashbury

[dusty]

Read this thread and you may find an answer to your problem. Reference post #11.