Use a Bottom-Bearing Bit for Template Routing
I use a top-bearing, flush-trimming bit for template routing, but it keeps digging into the workpiece. What can I do to prevent this?
Ron Edwards, Santa Monica, CA
The short answer is to use bottom-bearing bits. They have a distinct advantage over their top-bearing cousins. As the router moves around the template and workpiece,there is a chance that the router will tip outward as you shift your grip, because the power cord snags, or because it’s just not your day in the shop. If that happens when you’re using a top-bearing bit, the cutting edge is forced into your workpiece, taking a divot from its edge and ruining it. If the same thing happens with a bottom-bearing bit, there is no harm because the cutting edge moves away from the workpiece.
Another good tip for template work or edge-profiling is to use a D-handle router base or a wider baseplate that lets you concentrate more pressure on the side of the router that is supported.