Bandsaw Troubles

[John Gutmann]

I have THIS bandsaw with a normal wood blade on it. I use this blade to cut aluminum Lexan etc. pretty much everything because the other blades I have trued didn't "bite" enough off of the piece of material to cut at a reasonable speed. The problem I am having is I can't get it to cut straight at all. I usually have to turn the piece I am cutting so the blade is twisted while cutting at about a 30-45 degree angle to cut a straight line.

I don't know if this is normal on a bandsaw this small. This is also one of the reasons I hate using any bandsaw.

Also, does anybody know what kinda of table saw blade one would use to cut Lexan with?

[DonRotolo]

Although a small amount of twist can be expected under certain circumstances, 30 to 45 is far too much. (That doesn't mean I haven't experienced it - it's just that it's not good).

I believe the solution lies in the adjustments to the blade and path. The blade has some influence as well. Properly adjusting the saw will definitely minimize twist for a given blade.

First, the blade: For Lexan, a not-too-coarse blade - say 10 to 14 teeth per inch - would be appropriate. Too fine and you end up melting the plastic from friction. Too coarse and you end up with only one tooth on the material at a time, particularly with thin materials like sheets of plastic. Conventional wisdom dictates not less than three teeth in the material at all times. Also, a wider blade (front to back, not thicker) will twist less, but the radius of curves cut is greater. If you make mostly straight cuts, or gentle curves, buy a 3/8" or 1/2" blade.

Next, the adjustments. There are the following:

Blade tension: If this is off, lots of bad things happen. If you don't know how, read the manual. Very important.

Blade guides: There three points of guidance on a bandsaw blade: Left, Right and Behind. Left and Right are blocks of steel which are held in place with setscrews. The blade needs to ride almost completely within these blocks while cutting, with only the teeth sticking out forward. They not only need to be touching the blade with a slight force, but they need to be adjusted side-to-side to hold the blade in its neutral position.

Behind should be what looks like a ball bearing. It is adjusted front to back, and held in place with another set screw. This should be adjusted so the blade rides about 1/16" in front of the bearing with no load. As soon as you start cutting, the blade will move back and ride on the bearing.

These exact same adjustments are both below the table, and on the adjustable guide above the table.

Lastly, adjust the guide so it rides just a little bit - 1/4" maybe - above the workpiece. If you have it adjusted so 6" of blade is showing, the blade can wander all over. Not only does having the guide improve stability, it greatly decreases opportunity for blade contact. Trust me, it hurts. A lot. For a While.

Delta is a big company. If you don't have the book buy one. If you do, read and practice the adjustments.

Although the issue may not be related to this, I have found that when my saw is carefully adjusted - it takes me about 20 to 40 minutes to change a blade - the cuts are great. Let me know if you need more explanation of any of the above. Or, if you know all this and it still cuts sideways.

Good luck,
Don

[KenWittlief]

besides what Don said, get some material you can practice cutting. You might be pushing the material to one side without realizing it, making the blade twist.

Like most power tools, getting it to cut is easy, being able cut exactly down the center of a pencil mark, without tearing up the material, takes lots and lots of practice.

while you are cutting experiment a little. Instead of turning the material more and more try pushing it a little to the left or right and see what happens

or try turning it the other way. Power tools dont always respond like you think they should. you gotta develop a feel for it.

[Jay H 237]

If you're doing straight cuts (or attempting to ) you could try clamping a fence to the table. This should help, and since that one never came with a fence and piece of straight stock, wood or metal would work.

Another thing to be aware of. The blade guides, whether they're friction blocks on lower models or actual live bearings on better models, are attached to the blade guard on the top side. If you're cutting a 1/4" piece have the blade guard set for about 1/2". If you have it set up real high the blade will lack support close to the work and be able to twist easily.

Play with the speed at which you're feeding it like Ken said. With plastics they can, and will, heat up. If they get too hot they can melt and clog the teeth in the blade reducing you're cutting ability and causing it to wander.

[John Gutmann]

Originally Posted by KenWittlief

besides what Don said, get some material you can practice cutting. You might be pushing the material to one side without realizing it, making the blade twist.

Like most power tools, getting it to cut is easy, being able cut exactly down the center of a pencil mark, without tearing up the material, takes lots and lots of practice.

while you are cutting experiment a little. Instead of turning the material more and more try pushing it a little to the left or right and see what happens

or try turning it the other way. Power tools dont always respond like you think they should. you gotta develop a feel for it.

I know I am good on a bandsaw because on the ones at school I can cut dead center down a pencil line really fast. That is why I know something on my saw isn't right.


I tryed the fence Idea, the blade just walks the other way. i will try some of this tomorrow more, when people aren't sleeping. I was pretty sure I had it set up the right way :-\

[sanddrag]

My guess would be the blade tension is too low or the guide is too high.

[Gabe]

You could also perform a test by using different thicknesses of plastic, wood, and aluminum, noticing when the blade feels like it is running wrong. As sanddrag suggested, try adjusting the tension of the blade tighter. You could also be feeding too fast, which would cause the blade to twist off your marked line very easily.