Hey, Paul! Take a look at these: http://www.stewmac.com/shop/Fretting_supplies/Shaping_and_crowning/3/Diamond_Fret_Files.html They look much better than the older versions. My guess is that the wide fret file would have enough radius for capo work, and that it will easily work in the piano with the strings loosened and pulled down from the bar. You gonna buy it first? Ed Sutton
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