Originally Posted by
NEATman
Bill-
Here's a concept that just came to mind:
Perhaps if you make a new wood ring, just as you have now, but make it with a smaller ID. Mount it in place on the Z axis. Then invert your router with the bit sticking up, level it's base to the XY plane of travel on your router with an indicator. Clamp your router to the table in this inverted position, and use it to enlarge the hole in the clamp by programming a circle.
Your router mount should now be perpindicular to both the X and Y travel by as accurately as you leveled the base of the router to the travel.
The best part is no adjustment is needed, and you won't need to qualify anything before hand.
NEATman