For cutting precision circles few tools can compare to the versatility of a router. With this router compass jig you can cut circles from 8" to 48" in diameter. (60" with optional extension) 

The heavy duty Lexan jig attaches to almost any router. Embossed measurements help speed the process of positioning the jig. Once the proper measurement has been set the jig can be pivoted around the work piece to cut the desired circle.