Woodpeckers Slab Flattening Mill PRO guides your router over your slab in a controlled plane. Since you’re using a router instead of a planer-style cutterhead, tear-out is minimal… and thanks to our uniquely engineered rails and enhanced solid steel carriage, the surface will only need a light sanding afterwards. The router carriage adjust in height by a full 2-1/2”. Depending on your router bit, you can work on stock just a fraction of an inch thick or up to 3-3/8” without ever shimming either