This edge-guide works so well for breaking down sheet goods that I decided to dedicate a circular saw to it. I made the base from 1⁄4x12x30" melamine for minimal friction when making cuts. Take care to secure the rails parallel to the edges of the base, and the saw perpendicular to the rails. Then plunge the circular saw through the base to create a zero-clearance kerf. Remove the saw to adhere the scale tape to the base with the zero mark at the kerf's edge.