I was changing the strings on my Yamaha RBX170. When I took off the E string, a piece of the nut fell off. After looking around at GC and some local shops, nobody has the nut that I need. I was able to epoxy the broken one and it seems to be working for now. I did get referred to a guy in my town who carves nuts (LOL). He indicated that he uses Bone, copper and a couple of different composites. What is a good material to use and how can I ecxpect it to affect the tone?