I'm looking to replace the nut on my Epiphone Nighthawk. I heard the Graph Tech nuts are supposed to be self lubricating so the strings won't pinch up in the slots which causes tuning problems. Any of you guys have any experiences with Graph Tech, or is it just bogus?
They work, they're very good nuts. The Tusq XL and the black Tusq XL are the self-lubricating ones, their other nut products are just synthetic bone.
Self lubricating isn't quite right, they're made of graphite, which lets the strings slide similar to putting graphite from a pencil in the slots. The only one I Have was in my Peavey Patriot from the factory, I still have to use pencil lead or the strings bind just like a bone nut. Pretty good though, and hard enough it won't wear for a long time, I don't have any complaints about mine. That said I'd probably replace it with bone if it needed another one...If you want Graph Tech, go for it, probably would work well, other people seem to like them. Mine seems no different from the one in my Squier Strat as far as usability. Also don't know if it's the Graph Tech brand, just know it's graphite.
Hmmm...I wonder what this button does...
Isn't that self-lubricating? They release graphite when there's enough friction for the string to bite into the material.

Have you tried re-slotting the nut a little wider?