You'd think so, but the grooves in the nut are all cut at different widths to suit different gauge strings. Normally you will find that the headstock side of the nut will be bevelled or curved to provide a smooth curve for the strings to go over as they run down to the tuner stems. The fretboard side will be more or less straight up and down. Plastic nuts are less defined as they are generally moulded to shape, whereas a good bone nut, or a graphite nut will be hand shaped to preference.
DB has a good thread on this going in the "DB's Corner" section of the forum
http://www.buildyourownguitar.com.au...ead.php?t=5326
Edit: he says, coming late to the party!![]()