Sometimes when milling yellow birch, ash, and soft maple, I run into some chipping around knots, and even in seemingly "clean" areas of the board. Is it because of the grain pattern, improper kiln drying, lower-grade wood, or what? I do not have this problem with other species.
Do you mill hard maple too?
Several species have small pockets of swirly grain that result in chip-out now and then. This is probably what you are experiencing. The problem is exacerbated (I've always wanted to use that word) by moisture content (MC) of under 6 percent.
Gene Wengert, forum moderator