Project Information
Store bought jigs for cutting sound holes and routing rosette channels can cost from $100 to $200. There are circle cutting jigs for a lot less, but they lack a means for precise adjustment. The jig here was made after studying several commercial designs. Metal bushings were used to minimize play in the 1/4" metal pivot pin. The radius is adjusted using wing nuts to push or pull the carriage on the threaded rod, and lock it in place. The 10-32 threaded rod allows for fine adjustment - one full turn of the wing nut moves the carriage 1/32" or one half turn 1/64". The pictures show the very first use of the jig to route a rosette channel in a 1/8" plywood scrap. My original thought was that this would be a "prototype". However, it worked so well I don't see a need for further refinement.