I have a Grizzly G1073 16″ bandsaw which has been performing very satisfactory. It came with a 1/2″ blade and I recently changed to a 3/8″. After the change, I notice the blade wobbled from side to side. This is hard to describe. When addressing the saw table, the front of the blade (looking at the teeth) moves from side to side. I adjusted everything several times and then switched to a 1/4″ blade. The problem was reduced but not eliminated. All three blades are made by Grizzly. I have a link belt on the saw and have never experienced this problem with the 1/2″ blade. Tension has been adjusted according to the Grizzly manual and also per Mark Dinskies (Sp?) method outlined in his bandsaw book.
I plan to order a Timberwolf blade but before I do, I thought I would get comments from those more experienced than I.
Replies
From your description, I doubt it's the blade. First, check again making sure that all thrust bearings and guide blocks are well out of the way. Next, unplug the saw and rotate the upper wheel by hand, with typical tension on the blade. If you can see the variation here, check for periodicity. You could have a flat spot on the tire, or a spot on a bearing, so see if you can relate it to a particular position of either wheel or pulley. Also, see if you can measure the variation.
If it's not visible when turning by hand, then use your hand to apply force to each wheel and pully, in different directions.
If nothing shows here, you need a dynamic test. With the saw running and the doors open, use a light and a thin stick to look for a wobble. For this, I'd start with the motor pully and belt, since a wobble there will cause one in the upper wheel against the tension spring.
While a specific geometry in the blade could probably cause this, I suspect that you either didn't notice it with the wider blade, or the greater tension reduced the variation. If the latter, you might try the above tests with reduced tension. Under those conditions, a pully wobble would cause more bounce in the upper wheel.
Gerry
Because of the harmonic properties of bandsaw blades, changing the strain level (referred to around here by most people as tension) may dramatically affect blade harmonics (wobbly waves in the blade.).
Do all that Gerry suggests but also be willing to change the strain level while the saw is running. A slight change up or down may have a dramatic effect if you have hit a harmonic.
Somehow, I don't recommend you operating (running) the saw without your top and bottom covers over the wheels. If the blade jumps the wheels, I personally would not want the blade and all those teeth coming out/at me. Yep I am paranoid about certain issues of safety.
"Duginske's" book suggests you optimize tension or harmonics by backing off the tension until you see a slight wobble in the blade and then tighten 1/4 turn at a time until blade is running smooth. I tried this, and several other methods, and while there is some improvement, it still has a slight side to side wobble. It is interesting that the whole blade does not move side to side but when the teeth are angled toward the right side, then the back of the blade is to the left and vice versa.
Edited 5/22/2002 2:56:00 PM ET by KERFMAN
Did you ever find a solution to this problem? It's exactly what I'm experiencing on my Jet 14" saw and I can't for the life of me figure it out. I searched the archives and came up with your post. Thanks.
Gerry,
Exactly how does one do the dynamic test you are referring to with a thin stick.That sounds like a good test that doesn't require a dial test gage.Thanks Roland.
The simplest way possible. It may be hard to see how much a wheel is wobbling when it's in motion. I clamp a thin stick very close to the wheel rim or other area, pointed in the direction that it turns. Step back and turn it on and you can see the movement better on the edge of the stick. Other methods include a bright light. If you can cast a sharp shadow a little bit away, the movement is magnified.
Gerry
That would be Duginske
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Kerfman,
I have a Jet 14" bandsaw, and I learned the hard way what a big difference the blade makes. I used the Jet blades, then I tried the Olsen blades. All of them drifted and made imperfect cuts.
Finally, I switched to Timberwolf -- no more blade drift, and and perfectly straight cuts with no wobble.
Go to Woodcraft and get yourself a 1/2" Timberwolf blade.
Edited 4/20/2004 10:35 am ET by Matthew Schenker
If you look at the blade as you turn the wheel slowly by hand, do you see the wobble? It's a dynamic problem if it shows up only at speed, and not when you turn slowly. To help a dynamic problem, look for sources of vibration, particularly an unbalanced wheel. Varying the blade speed and/or tension can move the vibrations out of resonance so they do not cause as much problem. With the motor on, if you watch the blade for a while and it goes through cycles of small amounts of sideways vibration with gradually increasing and then decreasing vibration, that indicates resonance. You have various vibrations in the machine that don't individually cause a problem, but when they happen to be lined up with one another (in phase) they add up to a bigger problem.
If the blade vibrates little side to side at low speed, but twists, it's the blade. If you sight past the blade so you can see the direction it's pointed, you can line up your view so that you see only the edge and not the side. Note what's behind it on the wall. Now as you slowly advance the blade, check to see whether that remains the direction of the blade. If there is a significant change in direction, the blade is twisted and you are likely to get much better results with a different blade. At speed a small twist can cause a bigger wobble, and of course a lousy cut. If it does not twist, but does move sideways in some spot at low speed, it could be a kink in the blade that you might be able to take out, but that should not be present in a good blade.
Sawdust accumulating on the wheels can also mess up the blade alignment and cause vibration. If it cuts smoothly just after you clean it and gets bad later, installing a wheel brush may solve the problem.
I'm not an expert, but I've read Duginske's book, and I have an el cheapo bandsaw that I've now got running smoothly enough to easily pass the nickel test, and to cut smooth veneer < 1/8" thick. But it requres a good blade. On a cheap bandsaw (which I'm not suggesting yours is), I'd start by making sure the stand is solid: grab the table and try to rock the saw diagonally. If it moves more in one diagonal than the other, a leg needs shimming. You really don't want it to move at all; adjust the feet or reinforce the base until it doesn't.
I get the slow, side-to-side wobble even with the machine off, turning the wheels by hand, and even with brand new Timberwolf blades. It's driving me crazy.
Mark,
I agree that there must be something wrong with the saw. I have the same saw as you and my blade runs perfectly straight. It could be that the wheels are not aligned, but it could be something else. For example, the wheels themselves may be out of balance, with more weight in certain spots than in others. I've seen people fix this problem by using a drill to take out little pieces of metal from the wheel rims, thus balancing the weight. But I don't think you want to get into this.
If it were me, I'd return the saw and get another one. I forget whether you said you bought this saw new or used?
I bought it new about 15 years ago and it's given me great service. The problem just suddenly started to happen and continues to happen no matter what I do. I'm going to call Jet and ask how much new wheels would cost.
For anyone following this thread, or for those who found it in a search and are trying to solve the same problem, I don't have any good news. I spoke with Jet yesterday and they told me first that the wheels for my saw are no longer being made, and second that I should try re-aligning the joint where the top half of the saw is bolted to the bottom half. So I re-aligned that joint and had high hopes, but it didn't work. I still get the same side-to-side twist in every blade I try.
It's just bizarre.
At fifteen years old your saw could very well need new tires. Unless they are damaged in an accident, entire wheels are never replaced, why do you think you need new wheels?
John W.
Only because I've replaced everything else. Tires are brand new. Height adjustment mechanism is brand new. It's strange.
Mark,
Oh, that changes things! In a brand-new saw, I would figure it's a defect. In a 15-year-old saw, I guess we have to assume something went, like what the people at Jet tell you. If your saw is 15 years old, you got great service out of it. Maybe this is a good excuse to by a new one. The newer 14" band saws are nice!
That's the conclusion I'm coming to. It just bothers me that I can't figure out what the heck is wrong.
Have you checked the wheel bearings?Jim
Both sets brand new.
Wheel bearings or shaft wear?
Mark, you might give Louis Iturra a call. I don't have his number handy, but someone here will. He's probably forgotten more about bandsaws than most of us will ever know.
That said, we're coming into this a bit late. When I first read your post my first thought was bearings or excessive axial play. You indicate that after 15 years of faithful service, this struck out of the blue. Can you rememeber what you might have changed between when it worked great, and when it first didn't?
I really appreciate all the responses I've received. Again for the benefit of any person checking the archives in 2007, here is all the information:
--- Twist in the blade even at hand-turned speeds.
--- Same with any blade, old or new.
--- Brand new tires from Iturra.
--- Brand new bearings from Iturra.
--- Brand new upper wheel assembly.
--- Bottom and top wheels in alignment.
--- Spoken with Iturra - they don't know what it could be.
--- Spoken with Jet - they don't know what it could be.
It's a real mystery.
Does anyone have the number for Iturra? I've lost it and they don't seem to have a web site or toll-free listing.
If you set up the saw with the guides touching the sides and back of the blade do you still get the wobble when you turn the wheels by hand? If you do, the most likely culprit is the blade.
As a further test, mark the blade where there is a prominent wobble and continue to rotate the wheels by hand. If the marked spot shows the same wobble each time the mark is between the upper and lower guides then the fault is almost certainly with the blade. A lot of blades show some wobble when they are running free with the guides pulled back, but they cut just fine when the guides are bearing on the blade and a cut is being made. Are you actually having a problem getting a good cut?
John W.
Have you tried to move the blade a bit with the tracking?
I discovered that the method of tensioning the Timberwolf blade, where you move the tension up and down to get at the point where the blade doesn't flutter, actually achieves most of it's effect because the blade's tracking changes as you change the tension.
Also, a more basic question, does the slight wobble in the blade have any practical effect on the quality of the cut? If it doesn't why worry about it?
John W.
Matt, I know you're someone who investigates tools before you buy them, so which 14" bandsaw would you recommend today?
Mark,
Actually, after I did my research on Bandsaws, I bought the 14" Jet! I wrote a long, detailed review of it on Amazon, if you're interested in taking a look.
The 14" Delta was a close second. What I didn't like about the Delta was that it had a smaller table, the blade guard crashes down when you loosen the knob, and the lower guards are not as easy to access.
The Jet has been really reliable for me. Some quick points...
I still have the original tires. The Jet fence is great, locks down securely and is accurate. I bought Cool Blocks, and I added an extension rod for the blade tensioner. I use Timberwolf blades, and there is no drift at all. You do have to take it slow when resawing full 6" pieces, but I've done resawing with lots of maple, cherry, poplar, and other woods without a problem.
I'm considering moving up to an 18" saw, but I'm not sure about this yet.
Mark, the only thing I haven't heard you mention is what effect this wobble has on your cuts.
Are you unable to follow a line freehand? Is the blade drifting when you saw against the fence?
Also, have you tried adjusting the top wheel so the blade tracks off the crown towards the front (or back) edge of the wheel to see if this stops the wobble?
I have tried all kinds of wheel adjustments with no effect.
Because the blade is twisting from side to side, the cut is very inexact - you're fighting it the whole way. Also, because the back of the blade is twisting and therefore rubbing against the wood, it makes an incredible shrieking sound.
I got the number for Iturra and am going to call them today, but I don't have much hope of figuring it out. It's just weird that nothing works.
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