Fretwire dimensions vs fretboard slot dimensions

Dan Erlewine developed this remarkably handy look-before-you-leap gauge for quickly comparing the wire to the slot Simply hold the flat edge against the fret

The jig sits over the fretboard blank The fret cutting saw just fits in the slots and the acrylic being 6mm thick should hold the saw square I

fret slot saw StewMac sells a fret slot depth gauge, but you can also make one yourself with a razor blade or sheet metal stock (Mark Fogleman's suggested

fret slot depth Ideally the slot should end up 1o-20% deeper than the fret tang - the small gap underneath is filled usually with superglue Good luck