Your sawmill comes standard with a 2”, 9/8, 1” & 3?4” depth-of-cut scale with the kerf already calculated in. To mill specialty-sized boards, simply install one of the optional sets of magnetic scales calibrated with kerf allowance. When you want to mill standard lumber again, just peel them off and store them for later use. Each pair includes the primary and secondary scales. Imperial and metric scales available.