I'm curious about what happens to wood that's a bit warped or wonky when you joint and plane it after it's been well dried. My main question is: does this milling process help to stabilize the wood, or does it release internal tension, causing even more warping and shifting? For context, if I reclaim a cupped or bowed board and turn it into usable stock, will it remain stable after processing, or is there a risk of it moving again?
3 Answers
Every piece of lumber has some stress, whether you can see it or not. When you remove material, it relieves some of that stress and can cause movement. I typically rough cut my lumber, then let it settle before dimensioning it fully. The design can also help with stability—using frames and panels has been a tried-and-true method for centuries. For more insight, check out R Bruce Hoadley's book on wood movement.
Milling can definitely change the tension dynamics in wood. The bigger the piece, the more unpredictable its behavior can be after you shave off material. I usually let my wood acclimate in the shop for a couple of weeks after significant milling, then check for flatness before finishing the dimensions. This way, the smaller adjustments tend to reduce noticeable movement.
In some cases, it depends on the wood species. For instance, boards with gnarly grain can behave strangely during milling—one side might lift while the other drops, especially if the tree grew under uneven conditions. Quartersawn wood is generally more stable because it expands less with changing humidity. So while you can work with tricky grain, I wouldn’t recommend it for large surfaces like tabletops because you might end up with noticeable cupping.