Crooked bandsaw cut

[Ken Cohen]

I have a new G0555 bandsaw and just cut a curve in a 6" high piece of doug fir. Blade is aftermarket 3/8" and tensioned according to instructions.

The cut started fine (vertical) but ended skewed (fine on top of cut, way off on bottom)

Clearly, beginner's error: Is it tensioning, wrong blade, technique, other?

Thanks for the help.

Ken

[Stephen Cherry]

one thing to remember is that if you try to turn so sharp that the back piece of the blade touches the wood, all bets are off and the blade will start steering.

[John Bailey]

Many use 3/8" blades for curves, but I never use more than 1/4", even more so on a 6" piece of material.

Also, I would try more tension than is indicated on the saw.

[Roy Harding]

I have a new G0555 bandsaw and just cut a curve in a 6" high piece of doug fir. Blade is aftermarket 3/8" and tensioned according to instructions.

The cut started fine (vertical) but ended skewed (fine on top of cut, way off on bottom)

Clearly, beginner's error: Is it tensioning, wrong blade, technique, other?

Thanks for the help.

Ken

"Fine on top, way off on bottom" - this indicates to me that you need more tension. The blade is entering the wood, and then "bunching up" while in the wood - thus the "way off" on the bottom.

Try more tension (I'm not familiar with your particular brand of saw - but I've never met an onboard "tension gauge" which was even close to accurate).

Best of luck to you.

[Myk Rian]

One trick is to touch a fine stone to the back of the blade corners. It rounds them a bit, and gets rid of any roughness.

[Erik Loza]

Inadequate blade tension.

Erik Loza
Minimax USA

[glenn bradley]

I didn't see mention of feed-rate yet. The speed that you move the material through the cut can exaggerate this problem. Try about 1 inch per second and see if the problem reduces.

[Tai Fu]

Do you mean cutting through 6" thick piece of doug fir? If so that's a LOT of materials to be cutting curves into.

[Carl Carew]

All of the above make sense but I dis no see anyone mentiion checking the lower blade guides, I suggest you make sure that they are correctly set as well.

[Fred Belknap]

When I have cutting problems with the BS the first thing I do is install a new blade, about 90% of the time it cures the problem.

[Michael Dunn]

Everything said so far is logical good advice. What about checkin the table? Sure, it could very well be a lack of blade tension. However, it could very likely be that his table is not 90deg to the blade.

[Michael Dunn]

When I have cutting problems with the BS the first thing I do is install a new blade, about 90% of the time it cures the problem.

He did say he's using an aftermarket blade though...

[Michael Dunn]

I also would use a 1/4" blade for this workpiece.

[Prashun Patel]

The first thing i would do is check how it cuts straight. If the blade leans on a straight cut it is usually a dull blade or tension for me. If it cuts straight fine then the curve just may be too tight for the blade.

Also what is the tpi? If the tpi is more than 3 or 4 then you can have probs in thick materials.

[Ken Cohen]

Thanks to all for the helpful suggestions. I'll start with higher tensioning, since that is the easiest to fix -- along with a slower feed rate. If the problem is the blade, it's a tougher call since I rarely make curved cuts in 6" of stock.

Ken

[Lee Schierer]

When cutting a thick piece of wood, the feed rate becomes critical. A normal 3/8" blade has too many teeth to cut thick wood effectively at anything but a very slow feed rate. The bit of saw dust removed by the first tooth at the top of the cut stays in the gullet of that tooth all the way to the bottom of the piece and cannot do anymore cutting. The same is true of every tooth engaged in the wood. Too much feed rate makes the blade bog down and twist. A skip tooth blade will help as it allows the sawdust someplace to go on deep cuts.

Try more tension and slow your feed rate.

Also you didn't say what radius of curve you were cutting. Follow the blade manufacturers recommendations for minimum radius.

[Gus Dundon]

I think it's possible that if not all teeth are sharp, it would cause the band saw blade to skew it in the cut. Blade tension could also be a reason.

[Tai Fu]

blade being too dull is a big reason for excess drift... one clue is the blade cutting very poorly, burning wood and drifting like CRAZY. If you need to push a 4/4 piece through the cut with all your might, the blade is dull.