This is a quick router circle jig that I needed to make a 59" diameter table top from 3/4" thick cherry.
The materials required are:
7" x 36" x 1/2" plywood
1/4-20 Hillman joint connector
All materials are available at Lowes
Step 1: - Make the PADDLE
Note - I used a porter cable 1-3/4"hp router
Start by taking the base plate off your router - trace it onto the left side of the plywood. Now take a fender washer and trace around the base plate again which will give you an extra 1/2" border.
Now make a 4" diameter circle on the right side of the plywood. The distance between the two centers will be the radius of your new tabletop. (minus a 1/4" for the router bit)
Connect the large circle and the 4" circle using a straight edge and pencil.
Cut out the PADDLE using a table saw and band saw (freehand) - finish it off with your sander.
Using a 3" hole saw centered on the large circle cut out the center to increase visibility.
Now drill a 3/8" hole in the center of the 4" circle.
Take the Paddle and round over the entire perimeter (top and bottom) this will make the jig glide over the new table top when cutting the circle.
Step 2: Attach the Router
Using the footprint of your router base - drill 3 or 4 holes and countersink for the screw heads per the footprint.
Attach the Router without the bit.
Step 3: Attach the Pivot Point and the Hillman Connector
Mount the Dove tail follower in the center of the new table using three 1/2" screws. This will provide a very stable pivot point.
Place the "PADDLE WITH THE MOUNTED ROUTER" over Dove tail follower and the 1/4-20 Hillman connector will fit right inside from the top and sandwich the Paddle.
The last step is to remove the connector and install your router bit - reinstall and drive a 1-1/4" screw down the center of the Hillman connector into the table top.
I made 3 passes to cut through the 3/4" material.
Note - Once the paddle is made simply drill another 3/8" hole to change the table radius for future jobs.