Fretboard Radius Router Jig 9.5"

This jig is designed for the Dewalt handheld router with the 60mm x 60mm spacing on the plate screw holes. I printed each part separately and split them in half in Prusa Slicer in order to get both sides with the curve to print flat on the bed. I made sure to use connectors so I could glue the pieces together after they were done printing. If you do it that way, you can get away without using supports as well.

You can connect a 4" wide board to a nice, flat MDF board as the runner and then attach your fretboard to the top of that. Make sure the center of the fretboard is aligned with the center of the 4" runner.

This is designed for a 9.5" radius, but there's no reason you can't take the same idea and make one for a 12" radius as well.