Wavy lines in bandsaw cut

[Bert McMahan]

This sounds like a recipe for heartbreak. You don't want the spring collapsed, and you certainly don't want to go beyond that point.

The cheater bar is so I can grip the tiny knob better. I won't collapse the spring- I just don't have quite the manly grip that the designers envisioned when they made the tensioning knob

This bandsaw doesn't have a tension indicator on it and I haven't looked at the spring directly. The knob on top is just fairly small and slippery. I won't be cranking it so tight that things fail, I just can't grab the thing tightly enough. If it had a handle or something on it I could easily get the right tension.

I'll try a freehand cut and check for drift. I have checked the blade parallelism to the table when I first set it up, but I will recheck it to make sure it didn't get bumped somehow.

I'm also starting to wonder if the blade I got is just kind of sucky. I'll try a better brand with 1-2 more TPI since the saw doesn't have enough oomph to cut anything very thick anyway.

I'll also look into making a tension gage to put on there. I already have a couple of dial indicators that should to the job, I just need to make the brackets for them. Heck I can probably just make it with some clamps or something for a "how close am I" tension check. I should need to measure about 2 thou if my math is correct to get me to around 20 ksi.

[John K Jordan]

...
I'll also look into making a tension gage to put on there. I already have a couple of dial indicators that should to the job, I just need to make the brackets for them. Heck I can probably just make it with some clamps or something for a "how close am I" tension check. I should need to measure about 2 thou if my math is correct to get me to around 20 ksi.

Here is a picture and instructions on using a digital caliper as a free tension gauge.

http://www.sawmillcreek.org/showthre...33#post2640833

Or buy a Starrett tension gauge. It comes in a very nice red box.

JKJ

[Derek Cohen]

I don't think that you will get a better surface with more blade tension. Blade tension will aid in keeping the blade from wandering side-to-side (as will sharp teeth), and your cut is straight - indicating sufficient blade tension in a sharp blade. The surface is rough owing to too much set on the teeth of the blade. The answer is to get a better blade.

Regards from Perth

Derek

[andy bessette]

That waviness does not come from tooth set.

[John TenEyck]

You will never get 20 ksi on a 1/2" blade with a saw like that. Can't be done on a 14" Delta either. You will be lucky to get 12, but I would rather doubt that, too. But if you can it should cut just fine with a good blade. If you do measure the tension (a set of verniers and two tiny clamps are all you need) and come up with less than 10 ksi, then definitely go with a narrower blade. I'd just go there straight away if I were you, but I understand the resistance. I'm hard to convince most of the time, too, until I get to the conclusion myself.

John

[Derek Cohen]

That waviness does not come from tooth set.

Simple to test this: try a different blade.

Regards from Perth

Derek

[andy bessette]

No need to buy another blade. Just cut to a line as I suggested.

[Nick Decker]

Couple of things: I used a couple of those Powertec blades that Amazon sells, on a 10" Rikon that I had for a while. Regardless of whatever good reviews they got on Amazon, I found them to be cheap garbage, basically.

I don't think the Snodgrass method of blade centering (centering the gullets on the wheel) works for a small saw with crowned wheels. Centering the gullets will cause the blade to present a skewed angle to the wood; hence, drift.

I'd try a better quality blade, probably max 3/8" on that saw, and center the whole width of the blade on the upper wheel. And, please don't use a cheater to tension the blade. Very bad idea.

I would add that I followed a somewhat similar path as you. I bought the 10" Rikon, more or less, to kind of get an introduction to bandsaws. I learned a couple of things quickly: 1) They are addictive and 2) I needed a bigger saw.

[Ted Phillips]

Lots of good suggestions here. I've got one of these small bandsaws as well. I'd recommend getting a better blade - and keep it clean. This will solve a lot of problems. Also check the tires to see if they are wearing prematurely - replacing them can help your blade track better.

And one last suggestion - check your table to make sure it is exactly 90 degrees to the blade. Sometimes the blade wavers when it gets pulled out of line by the grain of the wood and if the saw isn't cutting at 90, then it flutters.

[glenn bradley]

I don't think that you will get a better surface with more blade tension. Blade tension will aid in keeping the blade from wandering side-to-side (as will sharp teeth), and your cut is straight - indicating sufficient blade tension in a sharp blade. The surface is rough owing to too much set on the teeth of the blade. The answer is to get a better blade.

Regards from Perth

Derek

I'm in Derek's camp if you have to use a bandsaw for these cuts. With the size of your stock and the desire for a good finish I would make these cuts at the tablesaw. Since no one has mentioned that I assume it is not an option. I expect to deal with saw marks off the bandsaw as a matter of fact in using this machine. Different blades and feed rates will vary your result but, you are not going to get hand plane, planer or even tablesaw finishes off a bandsaw. Minimizing the follow up is the goal.

I just factor in a run through the planer or wide sander as a follow up to a bandsawn surface. When re-sawing multiples from a single blank my routine is something like:
- Joint and plane the blank square.
- Resaw a piece off the blank.
- Re-run the blank through the planer to get a good face.
- Resaw a piece off the blank.
- Repeat till done.

One has to pause and reflect on the amount of effort being spent on trying to make something do a certain thing versus just altering the process. That is, I have found myself spending much more effort trying to achieve a perceived goal than the amount of effort required to just do it differently. It is part of my personality that can get away from me if I let it.

[Bert McMahan]

Thanks for the tips everyone. I did some more playing around with it last night and learned a couple things. First, this saw doesn't have a spring in it (that I can see, at least) so it's hard to say when I'm over-tensioning anything. I was able to get a better grip without a cheater and added tension, attempting the flutter method; this seemed to be doable as the flutter went away, but alas the crazy amount of waviness remains. No amount of hand-applied tension made any difference, so I gave up that route.

I have also ordered one new blade and will likely order a second slightly different one. Looking at the blade a little more closely it definitely seems to just be a sucky blade. It appears from a cursory inspection that each tooth is bent to one side or the other just slightly in an alternating pattern. I think there must be a few teeth that are way more bent than others, and they're just gouging the work. Running the part through faster means the wonky teeth are hitting at a lower rate than running it through slowly, hence the better cuts. Just a theory right now.

Regarding the surface finish achievable by a bandsaw- I have seen plenty of bandsaw cuts that are far, far better than what I'm seeing here. Perhaps the pictures don't do it justice but the waviness is completely unacceptable when I've seen much smoother cuts on similar bandsaws before. There's something wrong with either my saw or my technique, probably both

Last, the suggestion for using the table saw is a good one. This particular project with the stock I had would result in much less waste if I used the bandsaw than the table saw; I wanted 3 pieces sliced through the thickness. With my table saw I'd have only managed two slices, and I was hoping to get more usage out of this piece of wood. I am of course able to plane down the parts I showed in the original post, and I'm still ahead of where I'd have been with the table saw in terms of material usage, but it took much more time than just using the table saw in the first place.

I'll post back once I try with a different blade. What's everyone's favorite 3/8" or maybe 1/4" blade for a small saw?

[John TenEyck]

Glenn, your approach is what I used to do. Then I read from several members here how they could get glue ready quality straight off their BS when cutting veneer. With a Woodslicer blade (which I am not endorsing) on my 14" Delta I found I could get beautifully smooth surfaces, too, but any movement of the wood during the cut would bind the blade. Then I stepped up to a Grizzly 0636X and put a 1", 1.3 tpi Woodmaster CT blade on it. Now I get the cut quality I showed above with every cut. There is no need to rejoint or replane the stock after making a cut. As long as the stock doesn't cup or bow you can take slice after slice, saving time and increasing the number of veneer slices I get from a board.

How is it that the Grizzly can do this but the Delta can't? Blade type and the ability to tension it.

John

[John K Jordan]

...
Looking at the blade a little more closely it definitely seems to just be a sucky blade. It appears from a cursory inspection that each tooth is bent to one side or the other just slightly in an alternating pattern. I think there must be a few teeth that are way more bent than others, and they're just gouging the work. Running the part through faster means the wonky teeth are hitting at a lower rate than running it through slowly, hence the better cuts.

Bandsaw blades often have an alternating pattern to the set - e.g., left, right, center, left, right, center. You can check if one tooth is out of spec by holding something like the end of a ruler just barely not touching one of the teeth and rotate the upper wheel slowly by hand. If a tooth or so is way out of whack it will hit when the others don't. Check both sides.

However, the type of waviness you showed in the photo is probably not, in my experience, due to tooth set. That would leave a series of scratches, further apart when you cut faster. I've seen that when the blade is waving back and forth. When it happened to me it went away when I tensioned the blade properly. It might also be worse if a fairly wide blade is running well on the front of a crowned wheel so the back is pressing hard and the front can wobble back and forth. (I am by no means an expert but I get good results. I tune my bandsaws so the blade tracks in the middle of both upper and lower wheels. I like Duginske's book for how-to.)

If the blade is dull all bets are off. Run your thumb upwards over some teeth and see if you can feel the sharpness. If you aren't familiar with what it should feel like you might not be able to tell. Blades can do all kinds of bad things if not sharp, especially if not sharp or damaged on one side. A new blade will let you feel the difference instantly. BTW, I generally sharpen my blades several times before I install a new one. Depending on the wood a blade can get dull quickly, especially one made from cheap steel.

As mentioned earlier, if the guides are too loose this can allow blades to wander, especially if there are other problems such as tension or tracking. The blade can start to twist one way in a too-wide gap between the guides, then twist the other way, back and forth. The standard simple advice is to adjust the guides so there is gap between the blade and the guides the thickness of the paper in a dollar bill. I used to use a 2-dollar bill for good luck before I got the bandsaws figured out. Be sure to back off ALL guides before starting to adjust so none are touching the blade.

Most bandsaws have some type of thrust bearing that touches the back of the blade when it flexes as you push the wood into it. No part of the blade should touch this rear bearing or guide when you are rotating the blade by hand. If it does, it can put too much pressure on the blade and really mess with your cut, especially if other things on the saw are not right.

Another thing that will play havoc with the cut - a damaged blade. If it was ever caught in a kerf the blade probably has a bend in it. Sometimes these are difficult to see. If you removed the blade and lay it flat on, say, a flat concrete floor you might be able to see. Also, put a piece of wood or small square close to the side of the blade and rotate the upper wheel by hand - you might see if there is a bad place. While checking, see if the back of the blade runs true as well.

I'm sure you know this, but if problems persist on that little saw ... get a better saw! (Easier said than done!) I'm sure all of the 100s of people who have read this thread will gladly contribute a couple of bucks. Mine's in the mail.

JKJ

[Robert Hazelwood]

I used to have the Rikon version of this saw, and it would work pretty well with a 1/2" woodslicer, certainly much better than what you are getting from that amazon blade. But the woodslicer is thinner gauge than most other blades so it is easier to tension. Still, it had to be cranked down pretty tight, but no cheater bar was necessary A thin kerf blade makes a lot of sense for straight cuts on this saw since it requires less power to cut, because the motor is pretty anemic.

The woodslicer (or Kerfmaster from spectrum supply, same thing) doesn't come any narrower than 1/2", but as I said, this saw should be able to handle it. You can also look at the Lenox flexback blades, which are pretty thin and are available in 1/4" and 3/8" widths.

[Nick Decker]

"What's everyone's favorite 3/8" or maybe 1/4" blade for a small saw?"

I don't recall if I ever tried a 3/8" blade on my 10" Rikon, but a 1/4" seemed to work fine. Woodcraft sells Starrett blades in that width range, I'd check to see if they have one to fit your saw.