The hardened steel Fret Fitter has custom jaws for flattening the barbs to fit a tighter slot, or for pressing a slight scallop into the tang to fit an oversize slot. You simply vary the pressure of the tool as needed.
Works on stainless frets, too! All of our tools are suitable for use on stainless-steel fretwire, with the exception of our Fret Tang Nippers and Fret Cutters. Modern stainless-steel fretwire is known to be harder than the traditional nickel-silver blends, but our own shop experience indicates the wire does not cause premature wear of files or sandpapers.