I've had a 70's Fender project P bass now for a while, which I took the frets off of about a year ago, everything came out beautifully except when it came time to replace the old nut. I bought a fender made nut, I believe it's wood, I've never really seen one like it before but never the less, my only issue is, obviously I have to file it down to get any kind of action, as well as reduce the buzzing, on the neck. I have been doing it with sandpaper, as the nut is wood, but I can't really get the hang of shaping it. As the neck is curved and the nut is flat I've had to make the curve by hand, but I can never seem to get it well enough curved to sit flat inside it's groove. Is there some simple step that I'm missing or some common tool that I have overlooked?