This jig is handy for cutting purfling miters. The jig is made from a maple block in the shape of a c-bout inserted at an angle into a plywood piece used for clamping the jig to a work bench. This idea came from Olivia Pelling who taught me violin making while I built my first violin.
I use this along with a small very sharp chisel to set the purfling miter. After bending the purfling to shape on the bending iron, I mark the beginning and end of the mitre with a pencil and then cut on the curved surface of the jig so that the bend of the purfling is supported. From there it’s trial and error to adjust the miter cut to remove any gap.
A loop comes in handy to check the result.