pnj wrote:
The problem is because of the beveled edge meeting the rest of the fret, not the ends of the fret themselves. if that makes sense. I guess it's probably like a little burr from the file.
I do know what you mean. And on a uke it is a real pain. One of the problems of
playing the uke is that we tend to play with the right hand around the 12th fret for the tonal sweet spot. Now, when fingerpicking there, my nails "snag" on that little sharp edge.... which kinda upsets the rhythm.
So what I now do on my uke builds is to
round off the fret chamfers... both from the top of the fret to the fingerboard sides
and also around the end of those chamfers. The fret ends are now rounded in both planes.
Rounding from the top of the fret is easy...
Rounding the ends of the frets... I do with a small really fine toothed file (it has a non-toothed edge, so that helps not to mark the fingerboard, and only a couple of very light strokes are needed. Then finish with 1200 grit paper to polish them.

end result...

Rod