A method for generating a tool path for milling a region of a workpiece is disclosed. The region has a first side meeting at its respective ends a first end of each of a second side and a third side. The method includes the steps of: (1) determining, using a computer, a radius of curvature and a center of each of a succession of circularly shaped tool passes, each successive tool pass advancing into the region from the first side of the region, wherein the radius of curvature and the center of each advancing tool pass is determined such that an engagement of the cutter following the tool path does not exceed a predetermined value of cutter engagement, and (2) generating instructions for controlling the milling cutter to mill the region in accordance with the generated tool path.