Originally Posted by
John Coloccia
There's a lot of misinformation on this thread. I routinely work to a couple thousandths of an inch without doing any special at all. Whether or not it's a good idea for any particular piece is really governed by what you're working on, but the notion that you somehow CAN'T work to tolerances like this, or that it's difficult, is just wrong. Also, the notion that you can't work to these tolerances because the wood moves is misleading at best. Wood hardly moves at all along it's length. A quartersawn 1' wide board, going from 80% humidity in the summer to 20% in the winter, might shrink .1" across it's width, but that's across the entire width. A feature, such as a slot, will hardly change dimensions at all.
Anytime this topic comes up, there's always this broad brush stroke of, "Oh, you're just being silly...tee hee hee....the wood's going to move. What a waste of time". It's a bit more nuanced than that. Yes, at some level the wood does move, and at another level it just doesn't. In some places it pays (or is necessary) to be extremely precise, and in other places it doesn't.