What happened to the wood I just resawed?

[Tom Griffin]

Hello folks, I am a relatively new woodworker, and I have a question about some Jatoba that I am milling. I resawed a 5/4 board that is about three feet long and eight inches wide. I used my 1-inch resaw blade on the band saw. When I finished resawing, the boards immediately cupped. Neither have a flat side anymore. I resawed once before (cherry) and did not have this problem. Is it a problem with the species, or maybe the blade? The blade had only been used once before this.

Thanks for your help!

[Rob Russell]

I'd say either the wood wasn't evenly dry or you hit "reaction" wood. Reaction wood is when a board is from a section of tree that wasn't gropwing straight up, but leaning. The top and bottom parts of the tree trunk/limb are under different stresses and - when cut - can do all sort of twisty magic.

[Brian Triplett]

sounds like internal stresses to me. Sometimes when you cut the wood especially resawing the wood is not as strong and the stresses are releived by the wood moving. I'm not sure its a species issues, just that board.

[Frank Drew]

Tom,

This is exactly the reason why resawing isn't always the economical choice -- instead of one flat board in the thickness you want (plus a fair amount of waste in the form of shavings), you get two unuseable boards (and total waste). What I've found works best is to approach final thickness over a couple of days, reflattening and planing as necessary.

Resawing works when you have quite dry, very mild stock, but that last attribute isn't always knowable in advance.

I accept that others here who resaw all the time might have different, and better, experience.

[Lee Schierer]

Your cupping is probably due to moisture difference between teh center and the outside surfaces. Dense woods take a long time to acclimate all the way through to moisture changes. I would suggest wetting the concave side and then stacking the pieces with stickers about 6" apart and placing a lot of weight on the top. Leave it stacked for at least 2-3 weeks and then check the boards. They probably will be flat.

You may see the same problem when you start planing them unless you take the same amount off each face.

[Dewey Torres]

Good adive from Rob and Brian above. Jatoba (Brazilian Cherry) has a tight grain and this can happen (and has happend to me before too).

Dewey

[John Sanford]

I have a bunch of Jatoba that's been stored for the last four years, and when I pay off my bandsaw and pick it up, some of it is destined for resawing.

My question for those of you familiar with Jatoba is this:

Having spent 4 years in storage, non-climate controlled, here in the desert southwest, am I likely to encounter the moisture related challenges?

[Josiah Bartlett]

I've had the same thing happen with dry maple. I suspect reaction wood as well. If I'm going to buy lumber to resaw I try to make sure the grain isn't too gnarly.

[Peter Quinn]

You didn't mention your BS set up. Carbide teeth? Jatoba as you are aware is very hard and has the ability to dull HSS and carbon steel very quickly. It is plausible that resawing jatoba with a standard blade could dull the teeth mid cut and create a lot of heat, which could dull the teeth more, which could create more heat, and all this heat on one face of each side of the board can cause it to spring on you.

It is also possible that you have simply experienced the joy of Jatoba. It is not one of those woods that comes to mind when I think dead stable and easy to mill. It seems to be tension wood by its nature, having fought its way through a rain forest canopy to reach maturity. Pinging it with a finger gives a sense of the tension it holds, almost sounds like an instrument's tone wood. I have passed it over the jointer in hopes of flattening it only to have it spring the opposite direction in defiance of my wishes, then turned it over to attempt flattening the other face, same results! Beautiful, but difficult.

[Brian Kent]

I have a bunch of Jatoba that's been stored for the last four years, and when I pay off my bandsaw and pick it up, some of it is destined for resawing.

My question for those of you familiar with Jatoba is this:

Having spent 4 years in storage, non-climate controlled, here in the desert southwest, am I likely to encounter the moisture related challenges?

My guess is that 4 years in a Las Vegas desert climate is a pretty darned good kiln.

[Tom Griffin]

Thanks for all the replies. This board was the first one I resawed for this project, all the other boards were planed and jointed. I only needed half inch boards, so I thought resawing would make the wood go farther. Guess I will go back to the wood store and get some more.I suppose expensive lessons are the best ones learned.

[Bill Wyko]

I had the same problem with some Bubinga. I'm letting it sit through the summer and going to try again in the fall. It actually made a BANG when I got to the end of the cut. Then it was a cork screw.