Tension lumber

... wrt to reaction wood on 16x20 frame...

I know of no way other than restricting a piece of reaction wood from moving by another piece strong enough to overcome it, unfortunately. The only way you'll get around it w/ that particular piece of lumber will be to cut pieces sufficiently oversize and let it move before final milling.

Did you resaw the wood from 2inches into two 1inch thicknesses, or did you just rip 1 inch pieces off the original board? Did you find the board curving or twisting as it came off the saw (this is pretty obvious as it happens)? Did you allow the wood to acclimate to your shop for at least a week, before and after you resawed/ripped it (especially resawed)? It's also possible you introduced the twist when gluing up the frame, depending on how you clamped it. Unfortunately, I can't think of a way to salvage the frame short of cutting apart the joints, jointing and planing the wood as needed, and regluing it, slightly smaller of course. If you decide you have had it with that wood, I'll pay shipping to my house! ;)

What you might try is to find some angle iron and see if you can slot the frame on the back side and then screw the angle iron to the frame.

I ripped one inch pieces off the original board -- the original board had been in my shop for some time. I did not see anything unusual when ripping the board, but then I wasn't looking for any problem either. I worked the pieces that I ripped and glued them up within an hour or two. I doubt if the twist was induced when doing the glue up -- although I've read about this problem before, it's the first time it'd happened to me -- a real bummer! Thanks for the input.

"Compression wood", at least in softwoods is one or two tight growth rings that compensate for abnormal growing conditions, i.e., the tree grows on a steep slope etc... again, in soft woods it is readily identified as an extremely dark ring, and I suppose the same in other woods. When the tension in the tree is released, there is still compressed wood that makes for a tight ring. Sometimes, if you can identify the ring, you can rip on either side and the board will eventually straighten out (usually your just screwed tho..).

Sorry, sounds like a nice project... Schroeder

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That's unlikely to have been reaction wood that caused the problem then...more likely uneven moisture movement. Allowing acclimization of the pieces prior to final milling would probably have alleviated the problem.