I found this video from Eagle Lake Woodworking, it gives you a nice birdseye view of how to cut circles on the router table. 

• It highlights a miter track and a very unique jig that you need to use in that miter track.
• pivot pins
• locating the center of the board, prepping the board,
• drilling the holes
• gradual cuts raising the bit

This is a very slick set up and it looks like he uses some sort of automated or foot controlled way of raising the bit.

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