I may not be able to play guitar, but I can fix ‘em. If they aren’t too broken, anyway. This is the nwcMUSIC loaner guitar – the one we have to loan to people if they need one – and is the
second third! one I’ve repaired. (Spazzkat on Tumblr reminds me I helped fix one of his electrics.)
There’s not a lot of how-to involved, just get a block of that material – I don’t even know what it is – from somewhere like Dusty Strings, cut it down a bit with a hacksaw so it’s the right length and roughly the right height, then sand it with 100 grit until it’s the right shape. Add grooves with a sharp knife and use old strings to sand them into the right shape, and you’re done.
I had a guitar player check it out and he thought it played fine, like from the factory.
So, yeah, there. Now you can replace a broken nut on a guitar. Easy!