Originally Posted by fourstringbliss
I don't have any nut files and the original nut broke into pieces.
Nut files are not used for reshaping the bottom of the nut. A flat file or sandpaper on a level surface will suffice.
Fitting a nut is a labor intensive job that requires some specialized tools. It is a game played in thousandths of an inch. Good hand skills and experience working to tight tolerances is key. While some are able to improvise tools with varying degrees of success there is no substitute for having trained hands and a good eye.