I want to cut some boards to be used as the covers for a book. The boards would typically be about an eighth of an inch thick and book size in dimensions (the average book is 9" x 6"). What would be the best way to cut the boards to minimize the chance of warping? Since book covers are not attached to anything, there is nothing to resist the board from warping, so a cut is needed that will cut to an absolute minimum the chance of warping.
As I see it, there are two basic possible approaches. One is to cut the board radially through the log (shown as A in the figure below). The other is to cut the log like a salami, and then cut the rectangle of the board out of the salami slices (shown as B in the figure below).
Method A has the advantage that a smaller log could be used. For example, a 9x6 cover would require a timber of 6" diameter using the cut in A, but in B, the diameter has to be the length of the diagonal, or about 11" in the case of a 9x6 cover, which is almost double A. However, on the plus side, a single tree will provide a lot of salami slices, but only a small number of radial cuts.
Now, as I understand it, a tree absorbs water longitudinally, so in the case of A, moisture would be absorbed at the top and bottom of the board, so this could lead to the top and the bottom swelling more than the middle. However, in B, the moisture would be absorbed equally across the face of the board. So, based on this idea my expectation is that B would be less susceptible to warpage, but I am asking here to verify this idea.