How To: Fill Bar Fret Slots & Cut New T Fret Slots

Above is a '27 Martin 2-17 that had poorly-installed replacement T-frets. It originally had bar frets which take a wider slot.

The fanciest thing to do would be to go through the arduous process of cleaning the slots and fitting new bar frets, but from my experience with other bar fret Martins that have been swapped to T-frets, it's perfectly fine to fill the slots and refret with modern T-style stock as long as you do it correctly -- using the thinnest fret slot possible so you get enough "compression" from the fret tangs to keep the neck stiff.

Above is me filling the slots.

Above is after I've sanded the board flat (leveling) and polished it up (dressing). Here I show how I recut new slots by hand using a dozuki saw.