When I do a guitar neck refret job, I create this tool to confirm proper fret slot depth before installing the new frets. I bend a small piece of the fret wire into an ‘L’ shape and lightly file down the burrs on the smaller part of the ‘L.’ It’s never a pleasant experience to install new frets, only to find out that they won’t seat properly due to short slots or old glue residue in the slots.
–Kelly Butler