On 10-May-2004, "Max Mahanke" wrote:

Second, routing the cutout is easy with a router, a top-bearing mortise bit
the same radius as the corners of your insert plate, a drill, a jig saw, and
4 scraps of straight 1x2 at least 2" longer than the longest side of the
insert.

I went with the Veritas router plate. It's circular. Once you've drilled the
thing to adapt to your router's base, you use a supplied trammel and centering
widget and drill two guide holes in the base. Then all you need is to do is
drill a hole in the table, put in the centering widget and route two circles,
one on either side of the table. No bearing bits, no jigsaw and no aligning
bits of scrap to cut a rectangle. Even a fool like me could do it!

Mike