Glue-ups and growth rings

Does ripping and re-gluing drawer faces reduce cup? June 24, 2001

Q.
We do a lot of stain grade work with solid lumber drawer faces. Most of these drawers are under 7 inches cross grain. The average is probably 5 1/2 inches. We work with a lot of alder, maple and cherry.

Normally we would rip down the center of the heartwood, then alternate the growth rings at glue-up. This method does not produce the best looking blanks.

We prefer the look of a complete plank, i.e. we hope not to see individual staves after glue up. We would like these drawer faces to look as though they have never been cut. We have been ripping the planks in the middle and re-gluing them to look as though they have never been cut.

Have we accomplished anything useful with this effort? Will the cupping effects (associated with growth ring arrangement) be mitigated by this cutting and re-gluing?

Forum Responses
If I understand correctly, you have not changed the shrinkage behavior of the wood, just by cutting it down the middle. I think that you are not gaining any benefit.

Gene Wengert, forum technical advisor

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From the original questioner:
My assumption would be that no arrangement of lumber would mitigate shrinkage but some might have an influence on the tendency to cup.

Assume a six-inch wide board to have a potential of 1/8-inch cup. If this board was ripped and re-glued, wouldn't it then have two cups of 1/16-inch each? If I could spread out the individual cups, they would become less apparent visually.

Have I interrupted the natural tendency to cup by reducing the overall radius of the growth ring?

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If you had a cupped piece of lumber and ripped it in two and then re-jointed the edges, you would indeed minimize the cup. However, to rip before it warps will not affect the situation. Of course, the real key is to dry the wood well in the first place so that MC changes in use are negligible, etc. To really minimize the warp, you need to flip one piece over and edge-glue them together with one piece "up" and the other "down." Some people also flip end for end, but this is not needed.

Gene Wengert, forum technical advisor

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To minimize cup, try cutting the logs in half, splitting the log at the center rings! Then saw the halves in half the same way. This should take substantial pressure off the wood. I use this method to saw immature wood. After the triangular pieces have been dried, glue them into square cants and re-saw them to your desired thicknesses. I find this wastes less wood, too, and if done right you get even shrinkage throughout your boards!