I've never tried them, but my understanding is they don't last long, won't cut well on anything but plastic nuts, and are too flimsy to cut straight. However, I'm sure there they come in varying degrees of qualtiy, so the life expectancy complaint might be spurious. As for how they cut, my guess would be they're only as abrasive as they need to be to knock off carbon/dirt deposits in welding tips. I wouldn't think you'd want anything aggressive enough that it might cut into the inside diameter of those tips, right? It would change the orifice size, which I'm assuming would be NFG. As for their flimsiness, they're round, like wire. A round piece of anything that's only .010"-.050" in diameter isn't going to be too stiff. Cutting slots that aren't straigtht can leave you with strings that don't sound right. You get that "sitar" effect.
On the other hand, they are surprisingly inexpensive. You could buy 10 - 20 sets of tip files for what one set of good nut files will cost. That means maybe life expectancy isn't really a big issue. As for bite, maybe you don't cut nuts from blanks with the things, but they'd be fine for minor adjustments like you'd do during setup. The flimsiness issue could probably be overcome with practice.
If you don't cut many slots, it'd be a fairly cheap experiment to try a set and see how things work out. Worst case, you have to buy a set of nut files anyway, and maybe make a new nut. But, if you're already at that point, what's $5-$10 for a little education?
ccasion14:
