Wood shrinkage issue

[Bill Dufour]

40% must be a swamp in your house. where do you live, climate? How many years had the wood dried in the shop climate?
Bill D

[Robert Hayward]

40% must be a swamp in your house. Bill D

Really? Come over to Florida. Where 50% is considered desert dry. The hygrometer hanging on the wall above my desk is showing 53% inside and 69% outside right now. With 80 degrees inside and outside.

[Andrew Hughes]

There’s another wood movement condition to consider. Where the piece is sitting is there direct sunlight on on side during the day is it by a window. Is one side up against the wall and the other seeing air from a cooling system
I know it can make a difference. My wife’s dresser the molding have moved on one side. It’s the side that’s next to a window.

[John TenEyck]

40% is low, Bill, anywhere East of the Mississippi. But you guys make raisins out of grapes out there on the left coast, so I can see how that might seem high.

Back to woodworking, 40% RH is about 7% EMC. That's right in the middle of the target used by many folks who KD wood, including me. But the typical RH is higher than that for most of the year here in the East. KD wood in my storage shed often is 9 - 10% MC. I bring it into my shop and let equilibrate, but it won't come down at all in the summer when the RH in my shop is 50 - 60% (that must seem like a shower to you). In the winter, though my house will go down to 25% in really cold weather if I don't use a humidifier, which I do to keep it at 35 - 40%. If I build in the winter it's going to go up in the summer. Nothing new here, it has been going on as long as people have been using wood to build things. But you have to design and build to accommodate the seasonal changes in dimensions or things can go south. Close fitting drawers are a lesson in wood technology.

John

[Richard Coers]

Thoroughly dry doesn't mean anything. You need to test it with a moisture meter to know how dry it really is. No two boards ever act exactly the same. If I make snug drawers, I only use quarter sawn stock. That stock will not move in width, but instead very slightly in thickness.