The Workbench

Nut slot cutting


I have had issues setting up a few guitars lately and the issue after much adjusting ended up being the nut. Specifically the nut was cut too low. This resulted with having to adjust the bridge too high to stop fret buzzing etc. I discovered when depressing a string on the 4th fret that there was no gap between the second fret and the string. Checking other guitars that were set up nicely found there was a small gap. Searching information on the internet found a recommended gap of .0010 (10 thousandths of an inch) at the second fret. Adjusting the nut to this gap made a great difference in the height of the bridge. Have others had this issue and are you using a gap of .0010?


It sounds like you have a truss rod issue. The nut is out of play when you do any fretting. From what I’m reading you need to loosen your truss rod.


Thanks Curt, I tried adjusting the trust rod first. I think the trust rod on the guitar I am currently working on is adjusted properly with the proper relief. It is a set neck Guild Bluesbird. If I loosen the trust rod more it raises the strings so I could lower the bridge but then I get string buzz in the higher register. That is when I checked to see if the nut slot was cut too low. Do you prescribe to a gap of .0010 per my first post? Thanks again!


Maybe, I don't measure I eyeball it and then feel how it feels.

The first few are higher than the other from either the truss rod, a warped neck or popped frets.


Curt, you are a master, but I think you're misinterpreting what he's saying here. In fact, I'm sure of it.

First of all, you should depress the string at the third fret to check nut height by this method. As long as there's some gap, no matter how small, you have a good chance of avoiding fret buzz on the open strings. If the nut slots are exactly the same height as the first fret and every fret is perfect, all you should need to do, IN THEORY, is set the relief to accommodate your preferred string gauge and your playing style. No one actually does it that way, because it seems work only in theory, not practice.

Players and guitar techs have widely varying preferences when it come to the nut slot/fret relationship. I usually go for .014"-.018" higher than the frets on the bass side and transition gradually to .011"-.014 on the treble side, but some will go as high as .022" more on the bass side. The lower you go, the better your intonation on the first few frets.

You make those measurements like this: span two frets with something perfectly flat (a metal fret-rocker is ideal, but even a credit card will work) and use feeler gauges to measure the distance between the fretboard and the crowns of the frets. Then add on whatever amount suits your taste (see above) and hold the feeler gauges against the nut as you file, stopping when the file hits metal.

The fret slot should have a slight downward curve and open up slightly on the headstock side, especially on a vibrato-equipped guitar and/or an instrument without straight string pull (any guitar with a 3X3 headstock). It's a good idea to round the fretboard side of the slot ever so slightly — absolutely the smallest amount possible — on the fretboard side as well, but only for the wound strings, so that individual windings won't catch on a knife-sharp edge while bending or using the vibrato on fretted strings.


I should add that anyone with Curt's experience has every right to toss the feeler gauges and fussy numbers and do it however he wants. The procedure I outline above is intended for those who lack his time-won expertise.


Hi seadevil Sorry I haven't checked back in a while. Yes you have interpreted my question correctly. Thank you for your reply and explanation. I will follow your suggested measurements in the future.

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