Hi Larry.

One easy way to transfer correctly centered drill hole locations from your
router to the table insert would be to use an intermediate base made of a
flat, rigid and cheap material such as 1/4-inch hardboard.

Using your original baseplate, mark screw hole locations in a piece of
hardboard or other suitable material. Drill holes the exact size of the
screw used (no need to countersink / counterbore here) then mount the new
base on your router. If the base holes won’t align with the ones on the
router casting, you’ll have to redo the marking / drilling with suitable
corrections (this has to be precise). Mark the outside surface of the
board as “TOP” and an arrow to show the orientation you want for the
router once installed (remember that your router will be mounted upside
down on the table). Put a bit in the router collet of the same size as the
external dimension of the guide bushing you will put in the plastic insert
(you may have a 3/8, 1/2 or 5/8” inch bushing and a correspondingly-sized
bit).

Now plunge the bit through the hardboard plate. With a fixed-base router,
you may have to take special precautions to avoid motor wobble and
consequent precision loss. For this, you may have to partially tighten
whatever locking mechanism you have on the router and carefully lower the
bit into the base.

It’s almost finished. Insert your bushing in the plastic insert on the
table, lay the hardboard base over it (with the TOP marking showing) and
mark the screw hole locations on the table’s mounting plate. Double, even
triple check everything, be careful, and everything should be all right.
Then, take a deep breath and drill the insert plate.

Hope this help!

Andre from Montreal