Straightening Twisted Lumber
Rough lumber with a diagonal twist can be difficult to straighten, unless you use this trick. Joint the edges of the board and set it on a flat surface. Shim the two high corners, then rip two guide rails from scrap stock: their height should be the same as the highest spot on the shimmed board, and they should be cut from straight hardwood. Finish nail these in place, keeping the nails as close to the center of the guide rails as possible, so they never come in contact with the planer knives. Then run the assembly through the planer (or a wide belt sander equipped with a coarse grit belt), alternating the sides: the top should be up on the first pass, down on the second, and so on, until the board is flat. The guide rails will keep the board perfectly aligned.