Let me explain how I come up with these names. My Garage is 1/2 block away from my house. Just about everything I do I have to make at least 3 trips. So if after 6 trips 3 to make it and 3 to put it back, with stopping to take pictures it takes 10 minutes. I cut it in half.
OK - now the build. Using a 30 x 30 inch sheet I had left over to make a sled from the 80/60 build, I made a quick sled. I started by making a 17 inch square.
I then traced a rough circle I will sand the edges to remove material to allow this to be close to a circle it will be riding on. I will rub it down after sanding with bees wax, you could substitute bar soap.
the hole in the center doesn’t need to be accurate, it just needs to clear the business end of the router and leave enough material for the mounting holes.