Originally Posted by
Rob Sack
What about building a jig that firmly holds the work piece. Set up two routers. One with a chamfer bit with a top bearing and the other with a flat bottom "bowl bit" (I think that's what you call it) also with a top bearing to mortise out the hole. You would need a slightly larger bearing on the bowl bit so as to not remove the entire chamfer. Perhaps a disc sander on a shaft close to the diameter of the hole could be used to clean up the bottom of the mortised hole if necessary.