Step 3: First Fret Action
You should probably take it in if you need adjustments here.Your first fret action, or the distance between the strings and the fret wire of the first fret, is largely a function of the way your nut slots are cut. One indicator that your nut slots might need attention is if you get fret buzz when playing an open string. It could mean your nut slot is cut too deeply. If, on the other hand, the first fret is hard to play it might mean they aren’t cut deep enough. (Hey! This presumes you’ve done all the previous steps! If you haven’t, go back and do them!)
But, like with everything else, to be sure we measure. Time to bust out those feeler gauges again. No fretting, no capo. Just slide the feeler gauge in between the fret wire and the E string. Your first fret action should be about 20-thousandths-of-an-inch, give or take a couple thou.
If your first fret action is out of spec, especially if it’s giving you a problem, you should take it to an experienced guitar tech or luthier. I don’t recommend you do this yourself. It requires expensive nut files and using them is destructive. That is, if you fuck it up you’re going to need a new nut. There ain’t no do-overs here. Take it in.
On the other hand, if you’re feeling brave, or this isn’t your first rodeo, by all means go for it. But do yourself a favor. Don’t buy cheap nut slot files on Amazon. A good set of nut files can cost as much as a hundred bucks or more. Plus, if you have a guitar and a bass, they’ll each need their own set of nut files. Got guitars that use different string gauges? They’ll each need their own set of files, too. You can see this gets expensive quickly. That alone should convince you to take it to someone who already has all the right tools.
If you do this, it’s on you bruh.