Bending when resawing

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Forum topic by Laurent posted 04-04-2009 09:45 PM 2178 views 0 times favorited 13 replies Add to Favorites Watch
View Laurent's profile


41 posts in 4396 days

04-04-2009 09:45 PM

Topic tags/keywords: question walnut bandsaw resawing

This is my first time trying resawing. I took a walnut piece, jointed & planed it then resew it.
As soon as the 2 pieces were separated, the one against the fence bent pretty strongly (see the picture).
Is it normal? Due to the wood, or the process, or the fact that I did something wrong…

-- Laurent

13 replies so far

View Blake's profile


3443 posts in 4924 days

#1 posted 04-04-2009 09:56 PM

This is VERY normal. Welcome to the wonderful world of wood movement. Wood will move dramatically as its moisture level changes. The inside of the wood probably had quite a bit of moisture in it and when you cut it open, it dried quickly and warped in the process.

This is why it is important to work with wood that had been properly dried or “cured” before you can work with it. But even seasoned wood will continue to move (forever) as the atmosphere changes from season to season. This is why there are so many considerations in woodworking to allow for wood movement. There is no way to stop wood movement, only ways to allow for it without destroying your projects.

-- Happy woodworking!

View cmaeda's profile


205 posts in 4604 days

#2 posted 04-04-2009 11:04 PM

Wood movement is normal but also check the thickness of the resawn piece in various places across the end grain. If the thicknesses are all close to the same amount, it is wood movement. If the thicknesses are off, it means your blade wasn’t tight enough, you’re using the wrong blade or you were feeding the wood too fast.
When resawing wood, always cut it a little thicker than you need it to account for the movement because when you’re cutting the lumber, you are relieving any internal stresses that may have been in the wood.
I do notice that in air dried lumber, there isn’t nearly as much stress in the lumber as kiln dried.

View TheCaver's profile


288 posts in 4890 days

#3 posted 04-05-2009 12:23 AM

Yup, this is normal. It also depends on the grain direction and what part of the tree it came from….There are lots of variables….

I recall my first resaw, a beautiful piece of Jatoba that looked like a potato chip as it came off the saw….I didn’t allow extra thickness and learned a valuable lesson. Always mill extra thick and NOT to final dimension.

I rough mill to 4 square about 3 extra inches long (I can’t get my cheap planer to stop sniping), about a fat 1/8” or so over in thickness, and 1/2” or so in width. I wait a day or overnight then finish mill to spec as I build.

Another lesson I learned, don’t mill up parts you aren’t going to use within a week or so….even that is pushing it :) Unless you know the stock well and trust it ;)

Nothing worse than coping with wavy boards during a build….it just compounds as it goes…..Once you have square boards, then you can get sloppy, HA!


-- Somewhere, something incredible is waiting to be known. -Carl Sagan

View SST's profile


790 posts in 5245 days

#4 posted 04-05-2009 12:23 AM

From my experience re-sawing and even just cutting thicker pieces, even if they were dried properly, there are internal stresses or pressures and when you open up a piece by sawing it, these un-equal pressures can cause movement and even splitting or popping open.

It’s just the nature of the beast. It’s a natural product and prone to stuff like that. -SST

-- Accuracy is not in your power tool, it's in you

View Rob's profile


143 posts in 4980 days

#5 posted 04-05-2009 12:46 AM

I agree with SST. Try resawing European Oak!!

If the bow is not too bad, try lying the resawn boards flat with some heavy weights on top and leave them for a couple of days. Often when the stresses of heat and cutting are taken away, the timber will settle down again.
One thing, never plane or thickness freshly resawn timber, it just doesn’t work.




View Laurent's profile


41 posts in 4396 days

#6 posted 04-05-2009 03:32 AM

Thank you all for your different advises. Is cutting very thin layers even possible? I was hoping to be able to cut some 4/4 maple in at least 3 boards to use it as a kind of veneer over some cheaper wood.

-- Laurent

View marcb's profile


768 posts in 4724 days

#7 posted 04-05-2009 03:46 AM

Well, veneer slices can be 1/16th or less, which is very doable.

Once you get that thin the bow doesn’t matter as the wood is floppy.

As others stated you can sometimes reflatten the boards, and you might want to give that a shot.

View Laurent's profile


41 posts in 4396 days

#8 posted 04-05-2009 03:59 AM

thanks marcb, I’ll try both a 1/16” cut and also putting some weight on thicker boards.

-- Laurent

View oldskoolmodder's profile


802 posts in 4730 days

#9 posted 04-05-2009 04:01 AM

Don’t forget you may have to cover both sides of the “cheaper” wood to prevent cupping/bowing. Wood does strange things.

-- Respect your shop tools and they will respect you - Ric

View GaryK's profile


10262 posts in 5038 days

#10 posted 04-05-2009 04:05 AM

Fun, huh?

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

View Laurent's profile


41 posts in 4396 days

#11 posted 04-05-2009 04:18 AM

oldskoolmodder, I’ve never done some veneering yet, but is it what you do with veneer too? it’s kind of increase the price tag a lot then… I must miss something here?

-- Laurent

View oldskoolmodder's profile


802 posts in 4730 days

#12 posted 04-05-2009 04:24 AM

Depends on how cheap you go. There’s lots of good info on the web on veneering.

-- Respect your shop tools and they will respect you - Ric

View Laurent's profile


41 posts in 4396 days

#13 posted 04-05-2009 04:34 AM

thanks, I’ll look around. Laurent

-- Laurent

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