The NUT's importance in a proper setup

Here's a widely accepted industry standard which consistently works well with either nuts or zero frets. You can use a capo but it's really not necessary:

* Depress any string directly on top of the 3rd fret.

* Run your feeler gauges between the the string and 1st fret.

* Normal / optimal gap should be .003-.005"

* Nut slot angle and leading edge "break" are just as important.

Riis

 

This method overlooks the effect of "back-buzz" which happens between the fretted note and the nut. Often it is worth having a wee bit more height than by the method you suggest to avoid the problem. However, your method may work fine depending on the nature and degree of relief in the neck. Zero frets are often left a tad high for the same reason and to allow for a degree of string wear, since the zero fret takes a bit more abrasion than other frets from dragging the string across the fret when tuning.

 

My in the store, browsing basses quick check is: fret #1 and Look at gap at #2 (tap the string to feel the gap) Then fret #3 and check gap at #1 which should be same as gap at #2, if that makes sense. Not extremely accurate but a quick field test for a quick assessment of nut condition. Then I check that the nut slots have relief back from the leading edge so that the witness point is correct.

 

it is true that nice low nut slots are key to a good setup, and that stuff hanging in the store rarely has that done right.

break angle has no effect on intonation unless the strings are not "seated", i.e., unless they're still curving up off the nut or saddle and only straightening out towards the middle. pressing on them at the witness points to create defined, sharp angles and a dead-straight vibrating length of string eliminates the issue.

+1 to the "backbuzz" issue on certain basses if the nut is too low.

 

I thought it wasn't the break angle influencing intonation but the fact that the string stretches too much when a nut slot is too high.

 

Actually, both elements fold into the equation. You are correct about the nut slot height. If the slot topography is incorrect, though, the witness point may occur within and not on the leading edge as desired.

Again, a poorly cut and/or installed nut can upset what would otherwise be a normal set-up.

Riis

 

Ah, right, and with an improper witness point the scale length changes ever so slightly! I see.

The way I've been told to set up the nut slot is to angle it to the tuner as that creates a witness point as well as a proper angle coming over the nut, but then again I've only taken the sandpaper to the nut in one of my basses once to widen the slots (wrapped the string with sandpaper and gently rolled it over the nut slot until it got to the bottom of the already cut slot.)

 

Burnish the "backramp" from the fret edge of the nut to the tuner edge of the nut (as with a piece of an old string) and run pencil graphite in the slot to avoid string sticking.

 

This is basically how I do it.

 

I've found that OEM nut slots are always too high for my preferences so I adjust and ramp them accordingly.