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If it happens right away, it's totally expected. Much depends on the grain orientation of the original board but it's sort of hard to predict - maybe someone who understands wood science better than me will chime in. The bottom line is a cutting operation like resawing releases a lot of stress in the board. The resawn boards will move as a result of this.

I had a beautiful, beautiful piece of beech laying around that I had been planning to resaw for a special project. It bowed right after I resawed it the other day - approximately a 1/4" bow on a resawn board 3/8" thick. :( Somehow I have a feeling the more beautiful the board the more likely it is to warp after resawing!
 

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If the wood bows as you saw it it's internal stress on the wood and or being to wet. If it bows afterward it's due to not drying equally on both sides .you also need to make sure your band saw is set up to allow for drift. Also a sharp blade is important.
 

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Discussion Starter · #7 ·
Hi, Eric - I sometimes use air-dried wood (although it's harder to find, it seems), I just haven't tried resawing any of it yet. It may well be that my not-so-climate-controlled garage is making my stock moist.
 

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Bob,

Is the wood bowing, or are you getting what is called a "barrel cut"? Bowing is warping or twisting. In a barrel cut, if you look at it edge-on, one side is curved (CONVEX), and the other side-from the other side of the blade is convex. This is easy to fix. Make certain the saw is set up correctly; ie. the blade tracks in the center of the upper wheel, the table is square to the blade, and upper and lower guides are properly adjusted. If all this is done and you still get a barrel cut, you have a dull blade. They don't last forever, and even new ones sometimes have problems.

Michael Fortune had a very informative article on bandsaw set up in Fine Woodworking a few years ago. I followed his advice, and now I love my bandsaw. If you'd like, pm me and I'll e-mail a copy.

Hope this helps,

Steve
 

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Discussion Starter · #13 ·
Fussy - Yeah, I used that article to setup the saw! It's in FWW #173, Jim.

The boards come out like closed parens if you're looking down at them standing on edge, () . I think what you're describing is when they come out like this: (( ?

The blade is new.
 

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Trees that grow on hillsides or under other stresses will warp or bow when sliced; often times the board you purchase has been straightened out to look good to a prospective buyer. Resawing will re-release the tension, and you will need to straighten each piece out to use it. Wasteful and frustrating, but sometimes that is the way it is. But that is just one piece; if it happens every time, and with different woods, then it would be hard to blame the wood. Something would be amiss with your saw, I really doubt it would be technique (it's not rocket science). I would think to recheck blade guides and tension, maybe make an adjustment and cut a scrap piece for testing. Also another look at the blade you use in comparison to the thickness of cut you are making; there needs to be enough gullet to carry the dust out or your blade will wander no matter what. I hope this helps.
 

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I 2nd the last post. My guess is that the blade tension is too low. If you are getting the bow with several different woods, it's very unlikely all tension wood.

You also might want to try only quarter-sawn wood.
 

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When the boards are bowed. Are they the same thickness at the top middle and bottom of the slice or is the cut curved.

The curved cut is a problem with the bandsaw setup. Usually the blade (Sharpness, tension, drift and also a possabality of the blade following the growth ring line.
 
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