Cutting tools are provided that include a circular core with a cutting means located on its periphery, a central bore to receive an arbor of a rotating power tool and one or more perforations extending through the central core. The perforations are disposed along a circumference disposed concentrically with, and between, the central bore and the periphery. The perforations are arranged to form an annular window through the core which corresponds to a predetermined cutting depth during rotational operation of the tool.