Bandsaw Help

[Tim Dorcas]

One of the most frustrating tools in my shop is my bandsaw. I use about half time for veneers and the other half for general cutting. When it comes to cutting veneers my success rate if about 50%. Sometimes the blade wanders so much it ruins the wood. I have spent a few dollars upgrading it. You can check out what I have done here.

What are other people doing? Keep in mind I routinely adjust my bandsaw to make sure the bearing are aligned properly, the table is square to the blade. Somehow this should not be the tools that is giving me the most problems.

Thanks!

Tim

[Jason Beam]

What blade? What widths are you cutting? What kind of wood is it? How hard are you pushing the wood? How sharp is the blade?

All those questions should get us closer to diagnosing the problem.

[Tim Dorcas]

What blade? What widths are you cutting? What kind of wood is it? How hard are you pushing the wood? How sharp is the blade?

All those questions should get us closer to diagnosing the problem.

I can't think of the brand but it's a high quality blade. 1/2" 3TPI. I just put a new blade on so it's definitely sharp. Sometimes I go for 1/8" veneer. Sometimes a I try for 1/2".

[Paul Atkins]

I solved most of my band saw problems by throwing out my Tiwaneese 14" out in the yard and got a 20" PM87. Silk purse / sows ear syndrome.

[Burt Alcantara]

3 tpi is good for cutting green wood. For dry wood, I'd use something in the neighborhood of 10 tpi+. Depending on your saw's capability, you might consider a wider blade.

[glenn bradley]

It is disappointing to do as much bolt-on upgrades as you have and still not get a consistent cut. Although maybe obvious, I'll toss out some stuff:

- Face joint the surface that is against the fence and know that the surface that rests on the table is jointed at 90* to that fence riding surface.
- Upper guides are as close to the material as is reasonable. A well tuned saw is much more tolerant of guide height but with your symptoms I would give the blade all the help I could.
- Use a resaw (the knife-edge or pointy kind) fence for thicker material and compensate for drift on-the-fly. I sometimes have to do this on heavily figured woods but used to have to do it exclusively before I got my larger machine.

[Jason Beam]

I can't think of the brand but it's a high quality blade. 1/2" 3TPI. I just put a new blade on so it's definitely sharp. Sometimes I go for 1/8" veneer. Sometimes a I try for 1/2".

What kind of cut depth are you talking? 6"? 10? In dry hardwood?

How much force are you putting on the wood when you feed it? You should only be pushing hard enough to keep giving the blade wood when it has finished devouring what it's already had - a nice smooth pressure, the blade should set the speed.

Also, what kind of fence are ya using? Pivot point? Just a flat fence like a table saw?

I don't think a bigger saw is the answer - sure is easier to spend other peoples' money, though

The tooth count is DIRECTLY related to the thickness and I don't think we have enough info to decide if 3tpi is right or wrong. And, for the record, green wood blades aren't so much about the tooth count as they are the angle those teeth are ground to. The teeth are shaped differently for green wood than dry stock.

A 1/2" 3TPI blade would be okay in 6" and taller cuts of hardwoods and should track just fine under normal circumstances.

The rule of thumb with tooth count is generally to try and keep between 12 and 24 teeth engaged in the wood at any given time. A 3tpi blade would be good between 4" and 8" board. Down in the lower tooth counts, though, you start running into some practical limitations and I try to keep it as low as possible when resawing really wide stock. I have a 2-3tpi 3/4" blade that I regularly use in 12" wide stock - ripping ~1/16" veneers from.

Resawing is very much an exercise in getting to know your saw. If your blade is wandering so much that you blow out of a 1/8" slice, then you've got to look into things like tracking and blade drift. If your fence is not perfectly aligned with the cut (not the blade!) it will probably blow out.

I don't believe anyone should settle for very much, if any, drift in their blade - I shouldn't have to tilt my fence much at all. If my blade drifts more than a fraction of a degree, then I'm not setup correctly. It's worthwhile to setup your saw for as near ZERO drift as possible. If you have crowned wheels (most of us do on smaller saws), you can very very subtly adjust the tracking on those wheels such that the blade gets twisted ever-so-slightly by the crown of those wheels to pretty much eliminate all drift. Some folks don't think it's worthwhile, i leave you to decide for yourself. I don't have drift, i know others who don't have drift, so it really can't be all that tough to get rid of.

Anywho - a few of those questions above will help us to further diagnose the problem.

[Paul Atkins]

Jason, Oh I agree, bigger isn't always better, but better is better, and I wasn't trying to spend his money for him. Of the 10 or so machines I have, all were bought second hand and modified, tuned, tweaked to get the best out of them. I had a lousy 14" band saw for a long time and spent lots of time 'tuning' it up, but the cast iron frame was flimsy and would flex if I pulled down on it, the guides were sloppy, the wheels were not in the same plane till I shimmed them, and more I tried to forget. There is a point where you have to cut your losses or realize that the saw will not do what you want it to. The extra time to massage this saw to get a good product might not be worth it in the long run - Seems like Tom has done quite a bit to make it as good as it is. Yes, no drift is good.
Tom, is there someone locally that has a different saw and would let you try a few pieces on to see what another saw feels like?

[Tim Dorcas]

What kind of cut depth are you talking? 6"? 10? In dry hardwood?

How much force are you putting on the wood when you feed it? You should only be pushing hard enough to keep giving the blade wood when it has finished devouring what it's already had - a nice smooth pressure, the blade should set the speed.

Also, what kind of fence are ya using? Pivot point? Just a flat fence like a table saw?

I don't think a bigger saw is the answer - sure is easier to spend other peoples' money, though

The tooth count is DIRECTLY related to the thickness and I don't think we have enough info to decide if 3tpi is right or wrong. And, for the record, green wood blades aren't so much about the tooth count as they are the angle those teeth are ground to. The teeth are shaped differently for green wood than dry stock.

A 1/2" 3TPI blade would be okay in 6" and taller cuts of hardwoods and should track just fine under normal circumstances.

The rule of thumb with tooth count is generally to try and keep between 12 and 24 teeth engaged in the wood at any given time. A 3tpi blade would be good between 4" and 8" board. Down in the lower tooth counts, though, you start running into some practical limitations and I try to keep it as low as possible when resawing really wide stock. I have a 2-3tpi 3/4" blade that I regularly use in 12" wide stock - ripping ~1/16" veneers from.

Resawing is very much an exercise in getting to know your saw. If your blade is wandering so much that you blow out of a 1/8" slice, then you've got to look into things like tracking and blade drift. If your fence is not perfectly aligned with the cut (not the blade!) it will probably blow out.

I don't believe anyone should settle for very much, if any, drift in their blade - I shouldn't have to tilt my fence much at all. If my blade drifts more than a fraction of a degree, then I'm not setup correctly. It's worthwhile to setup your saw for as near ZERO drift as possible. If you have crowned wheels (most of us do on smaller saws), you can very very subtly adjust the tracking on those wheels such that the blade gets twisted ever-so-slightly by the crown of those wheels to pretty much eliminate all drift. Some folks don't think it's worthwhile, i leave you to decide for yourself. I don't have drift, i know others who don't have drift, so it really can't be all that tough to get rid of.

Anywho - a few of those questions above will help us to further diagnose the problem.

If there is something else I can do to improve my blade drift, I'm all ears. Right now my blade drift is very bad so this could be a good learning exercise. Thanks!

Tim

[Wilbur Pan]

I don't believe anyone should settle for very much, if any, drift in their blade - I shouldn't have to tilt my fence much at all. If my blade drifts more than a fraction of a degree, then I'm not setup correctly. It's worthwhile to setup your saw for as near ZERO drift as possible. If you have crowned wheels (most of us do on smaller saws), you can very very subtly adjust the tracking on those wheels such that the blade gets twisted ever-so-slightly by the crown of those wheels to pretty much eliminate all drift. Some folks don't think it's worthwhile, i leave you to decide for yourself. I don't have drift, i know others who don't have drift, so it really can't be all that tough to get rid of.

Crowning the wheels is the single most useful thing I did on my old bandsaw. I was able to get drift free cuts after this. The only thing that crowning the tires won't fix is if the blade is not square to the table in the front to back direction, but it will kill any drift you have.

I'll even go out on a limb and say that properly crowned tires is more important than making sure that the wheels are coplanar.

[Myk Rian]

Here is what I do'
Center the blade on the tires, after making sure the wheels are co-planar.

Adjust the guides properly. I use wood guides so the blade can be buried in them.

Take a piece of stock on edge, draw a line down the center of the edge, and resaw it without using a fence. Guide it manually. Use just enough pressure to keep it moving.

Once you get 1/3 or so of it sawed, notice that the wood may be on an angle. Hold the wood steady and stop the saw. Draw a line on the table using the wood as a guide.

Remove the wood from the blade, loosen the fence adjustment bolts, and align the fence to the line you drew. That is the blade track/drift.

[Jason Beam]

If there is something else I can do to improve my blade drift, I'm all ears. Right now my blade drift is very bad so this could be a good learning exercise. Thanks!

Tim

So if yer tires are crowned, start by getting the blade to ride in the center of that tire and tension and get everything lined up right (guides, etc). Make a cut now. If you have drift at this point, you can fiddle with the tracking (move the blade forward or backward) on the tire just a slight bit to reduce and/or eliminate any drift you might have. The crown causes the blade to twist just a little bit and you can guide that twist some given the position on the tire.

I can say that I have never adjusted either of my saws' wheels to be coplanar and I've got ZERO drift. I refuse to believe that I'm just lucky, given two different saws, different ages, different blades, different sizes, different makers ... no, it's not a coincidence. Nobody should have to tilt their fence to account for drift. Some do, and that's entirely their choice. I chose not to

Once you have worked out drift, you should be smooth sailing after that.

EDIT: It doesn't take much at all - 1/32-1/16 fore or aft will have a pretty significant impact on the drift line.

[Lance Norris]

Tim... you say the bearings(guides) are adjusted correctly. For resawing, if they are bearings, adjust them tight to the blade, so they are spinning with the saw running. Adjust the upper guide so it almost touches the top of the wood, and use a featherboard. I was amazed how much better my resaw results were when I started using a featherboard. Listen to the comments about adjusting for drift, remember that drift is a quirk of each blade and not the saw, If you change the blade, then the drift will be different. I have had the best results using a 1/2" 3 tooth blade on my 14" cast iron saw.

[Frank Drew]

Tim

Correctly tensioning the band can help eliminate some problems with band saws, and it's often more tensioning than you think.

One argument in favor of bigger bandsaws: You can increase the tension on a big saw more than on a little one because the band is under less stress curving around a bigger wheel -- or so I've been told by someone who had lots of experience with large saws cutting parts for pianos, an operation where blade drift was intolerable.

[Ted Evans]

You have received a lot of good advice Tim so perhaps I can add some confusion. I have a 15” General bandsaw made in Canada that has a very good reputation but until just a few months ago, its use was primarily for cutting curves. I had done some limited re-sawing by using the pivot point method and following a line, which worked for me, sort of. The fence I had was worthless when trying to rip something to thickness.

Then I bought a Carter blade stabilizer and was given the video (http://www.woodcraft.com/product.asp...FamilyID=21176)
by Alex and Howard Snodgrass on tuning a bandsaw, it changed my perception of the bandsaw completely. I turned it the way their video suggested and was amazed at the difference. I had always centered my blade on the tire, thinking that was where it should be. Their instructions were to place the gullet of the blade on the crown of the tire. I found that I had much less drift with any blade from ¼ to ¾ when doing this.

The next huge, and expensive, investment I made was the purchase of a Laguna Driftmaster fence. Drift can be adjusted for in a matter of seconds with this fence, if needed but the real advantage that I see was the incremental adjustment feature which allows the thin veneer piece to be cut on the outside of the blade as opposed to being between the blade and the fence. You may see a video of the fence at, http://www.lagunatools.com/bandsaw.driftmaster.aspx#.

I was in mourning for two weeks about spending that amount of money on a fence but now I would replace it without a second thought if it was lost. It is amazing to me how much I now use the bandsaw and not just curves and re-sawing veneer. It is wonderful what a well-tuned bandsaw, a good quality blade and fence are capable of doing.


Bear