There are several things that can lead to cutting into the face of the material:
- The router bit can be exposed too much. Because the bit is angled, the further down it extends from the router base, the more it will cut into the counter and eventually the face. Start off with the bit just barely exposed beyond the base. Make a short trial run and adjust down if not cutting enough.
- The router base, especially on small laminate trim routers, is typically only supported from one side & is prone to bending over time. If that is the case, the bit may cut in too deep for the same reason as above.
- If the router base is flat, smaller bases like on the trim routers lend to tilting the router a little & causing the bit to cut too deep in some places. It’s imperative that the base stay dead flat to the countertop when running along the edge.
- Lastly, if the front edge of the countertop is not a true 90 degrees, or within reason, and particularly if the bottom of the front edge is angled back, the bearing will ride inset from the top edge you are trying to bevel and the bit will cut into the face.
