I just purchased a new 14" Grizzly Utltimate Bandsaw with a 6 inch riser block which gives it a 12 in capacity. After setting it up and following the directions for tensioning the blade and setting the glade guides (it has sealed bearing guides) it decided to test it out using some scrape 3/4 plywood I had. Cutting straight lines went fine, sure there was lead but that is to be expected. However when attempt to cut a curve of about a 6 inch radius, the blade just twists and the cut remains relatively straight. It has a 3/8 skip tooth blade that came with the saw. I am sure it is a cheap blade and plan on replacing it with a 3/16 inch TimberWolf blade. However it seems like I should still be able to cut a curve with this blade.
Any ideas why it just twists? The thrust bearings is are thickness of a business card from the blade and the guide wheels are just slightly touching the blade. The blade guard is down to 1/4" above the work piece.
Are the guides adjusted out far enough so they bear on the blade just behind where the teeth are set? And you adjusted both top and bottom guides? Can you cut a shallower curve OK?
If the blade is twisting, the guides aren't doing their job.
I have the same saw and found the roller bearings to be a PITA - they work off eccentricity and I found it difficult to adjust them properly. I ordered the parts from Griz to hold standard guide blocks and not only is it easier to adjust, it's a different saw. It cost $5.00 to switch it over and I think it was the best $5.00 I've ever spent - with the standard rollers, I was ready to sell the saw and buy a Delta.
a business card is a little thick; I think most people recommend a dollar bill (whatever that mikes out to, but I'm guessing half that of a business card).
6" radius turn with a 3/8" blade (particularly a skip tooth) seems tight to me.
I think it was already mentioned that the guide blocks should be just behind the gullets in the blade.
Try a series of curved cuts with larger radii and work down to the smallest that the blade will do without twisting. Surely it'll cut SOME curve. I think you'll find that #2 in my list is the primary answer, but a combination of all three certainly would make sense.
Doesn't seem at all tight to me. I have no trouble at all cutting even tighter curves than that, with a 1/2" blade. A decent 3/8" blade should be able to cut a curve with radius of less than two inches.
-- Regards, Doug Miller (alphageek-at-milmac-dot-com)
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First suggestion: Change the blade. Second suggestion: Tell us what kind of blade (incl. teeth/inch)
Yes, thrust bearings and guide blocks do help things. However, I always test new blades with both out of the way. For the curve and wood you stated, I wouldn't have any problem cutting it without any blocks or thrust bearings.
I'm assuming you have reasonable blade tension, reasonable feed rate, and that the saw came with the typical blades they ship them with.
Curious,... on that note, the typical blade shipped is too small for the riser extension, which would mean you bought another blade of some type. While some of the cheaper blades are not too good, they are typically much better than what ships with the BS, and I wouldn't expect those results. Typically, a blade costing about 1/3 less than the TimberWolf should still give reasonable performance, so what gives here?
One other possibility comes to mind. I assume you installed the riser. Did you then check the BS alignment fully? I have a Jet-14, and had to knock the pin out of my riser in order to get the wheels aligned with the blade centered in the table slot.
Well, that's too much gap between the blade and the thrust bearings (the thickness of a piece of typing paper, or a new dollar bill is more appropriate). It's unlikely, though, that this is enough, by itself, to cause the problem you describe.
The guide wheels may not be properly positioned: the wheels should be just behind the gullets between the teeth. You may not have enough of the blade supported between the guide wheels.
And you may not have the blade tension set high enough.
You don't indicate your level of experience with bandsaws, so please pardon me if the following is way off the mark, but the trouble may be in your technique. To cut a curve with the bandsaw, it is necessary to feed the wood into the teeth _as_ you rotate it through the curve. Simply rotating the workpiece, without feeding it at the same time, will twist the blade but not cut anything. Same principal as driving a car: just turning the steering wheel won't get you out of a parking space. You gotta be moving forward in order to turn.
-- Regards, Doug Miller (alphageek-at-milmac-dot-com)
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I am using the blade that came with the riser block kit, It is a 3/8" x 105" x 6 TPI blade. I am not sure who is making them for Grizzly but their site claims it is made in the USA.
Interesting that you say you test without the guides in place. I always thought that was a no/no.
I just double checked all of the alignments on the BS and everything looks fine. Table is is square and plumb to the blade, the wheels are coplaner and the blade is ridding on the crown of the wheel.
I don't have another blade to test with so, I'll stop and pick up one from the local Woodcraft store tomorrow. This is my second BS, I originally had a 12" Delta but it was underpowered for what I want to do. I wouldn't call myself a begginer but I am definitly not a season verteran on the BS.
This is my second BS, I originally had a 12" Delta but it was underpowered for what I want to do. I wouldn't call myself a begginer but I am definitly not a season verteran on the BS.
I just moved every the thrust bearings closer and readjusted the guide bearings so they are 1/64 behind the gullet on the teeth. (They were about 1/32 to 1/16). But still have the same results. I insured that I was rotating the board as I feed it into the blade at a reasonable rate, but still the same thing. I can cut circles in cardboard just fine :-) But even in 3/16 thick ply it twists. I even tried turning up the blade tension.
I'll get a new blade tomorrow and see what happens. Currently blade is a grizzly blade, 3/8" x 105" x 6 TPI blade.
I'd really suspect he tensioning. I've cut curves fine using a properly tensioned blade with out the thrust bearings. As long as the blade is sharp, should be no problem. Of course, this is only for testing.
I'd double check the spring also. I have a griz 0555 and the first time I tensioned it, I had problems. Took a bit but I found that the screw thread in the tensioning spring had hung on a rough spot so it would appear to be tensioned when it wasn't. Fixed that and all has been well since.
You stated in an earlier post that you were able to cut a straight line with the blade. You did better than I did with the blade that came with the Grizzly kit for my G1019. A good blade solved my problems. When I ordered the kit a Grizzly tech support person suggested I purchase my blades from someplace other than Grizzly.
-- Jack Novak Buffalo, NY - USA (Remove "SPAM" from email address to reply)
Well, this is slightly embarassing but I've had the same problem with the same saw. It was caused by me misadjusting the side roller bearings compared to the back thrust bearing. I ran the saw for just a few seconds, which was all it took for the side rollers to whack the set out of the blade and knock off part of the blade tips. That blade would continue to cut straight, but without a decent kerf it just wouldn't do a curve. The problem was easily solved with a new blade, at a lesson cost of $25.
Of course your problem could be different. I just mention this as a possibility.
Ahhh....a BS manufacturer supplied blade...in THAT case... Here's a good one to try: cut the circle in the OPPOSITE direction. Not a real solution, and I'm actually just curious, but that will tell you if the teeth are worn (or bad) on just one side. In any case, I'd go for a new blade.
Regarding the guides, they do help, but when and how much will rarely be found in the books. It's the narrow blades that need the thrust bearings more (fairly obvious), and the guide blocks do little except for cutting curves, unless you hit the edge of a knot or hard curved grain.
Maybe four years ago on the wreck, a bunch of us looked at resawing 4-12" hardwood, and what blades and technique would produce the best results. With a good blade on a well tuned BS, one test involved setting the guide blocks nearly touching, maybe 4 mils away, and removing them entirely. Examining the roughness of the cut, I couldn't find any difference. A similar test with the thrust bearing (note: 3/4" blade here) showed little effect until the bearing was actually deflecting the blade at all times. Further examination showed the blade weld wasn't perfectly straight (flat, linear, whatever). IOW, if you placed the blade back down on a jointer bed, you could measure about an .032 gap.
This is an item I've never seen mentioned in any woodworking books. From machinest's land, a typical tolerance here would be .004. The blade distributor didn't know what it should be, but agreed .032 was too much and sent me new blades. These measured (I think...) .010. Rerunning the previous thrust bearing test, I found less effect from the bearing, and the resultant smoothness was better in all cases.
An easy way to get a quick measure of this in place, is to rotate your upper wheel by hand, while measuring the min/max movement of the back of the blade. Of course this brings other adjustments into it, but it's quick, and if it's good then it's good.
At the other extreme, both the thrust bearing and guide blocks helped when I was cutting many curves in 6" hardwood. I also learned (after the fact, of course) to vary the direction instead of cutting all curves the same, which will wipe out only one side of the blade.
If memory serves me right, I believe that John White was the only author who really discussed this in detail, and I highly recommend his articles.
I have the same problems you encounter and I bought two Timberwolf's blades and I am disappointed. So I got Lee Valley 1/4" blades, it work like a charm. I can saw very tight radius including resaw up to 11" .
Try Lee Valley blades it cost no more than Timberwolf, but perform better. Do you trust Lee Valley? Almost everyone here will tell you Lee Valley is a good company to business with.
Some people use a dollar bill for band saw set up, some use a hunnert. For the thrust bearing I back it off, the bearing, not the dollar bill, a sixteenth or so then start the saw up and slowly (vewy, vewy slowly) start to dial it into the back of the blade until it just starts to spin intermittently, vewy, vewy intermittently.
Now, an embarrassing question, and you don't have to answer, is the blade on right side down?
"Vic Baron" wrote in news:qOvYc.9462$ snipped-for-privacy@newssvr21.news.prodigy.com:
That was my first thought. But he mentioned turning up the tensioning, with no effect. He also says he can cut in something soft (cardboard), but not in wood. So my guess is that his blade has no set, and the back of the blade is binding against the side of the kerf.
Nate Perkins and John McCoy were right on the money. I stopped by WoodCraft and picked up a new 6TPI 105" Timberwoof blade today. Before installing it I checked the set of the teeth of the old blade. Yep, they were almost dead even with the rest of the blade. So off it went, on goes the new blade and everything is great! I am able to make cuts the size of nickles while pushing the wood with 1 finger and no effort.
I suspect that in my early "tuning" now called "butchering" of the setup, that I got the guide bearings to close to the teeth and that pinched them shut. I checked the 93" blade that came with the saw and the set is proper on it.
Thanks for Everyones advice, I now know and understand what happend and how to prevent it in the future.
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