The NUT's importance in a proper setup

Discussion in 'Hardware, Setup & Repair [BG]' started by edpal, Jul 9, 2013.

  1. edpal

    edpal Inactive

    Oct 3, 2007
    I've looked at all the stickies on setup and notice everybody avoids the height of the nut slots. No mentions of string break angle throwing off intonation in lower frets, no discussion of the how low a person can go with the nut (.010"/.25mm at first fret) without buzzing on open notes. Nothing, nada. Instead, they start with discussing the neck bow and playing action and adjusting the saddles for intonation.
    Reason I started this is I have worked on 4 basses in the last 2 months that all had the same issue straight from the factory and a store setup - super high nut slots which made getting good intonation on the first 4-5 frets impossible due to break angle issues.. Here's the basic theory I work under on nut slot height:
    1.Fret (capo is better, more consistent) behind first fret with light-medium pressure, pluck string. IF no buzz we can continue and check the distance under the string at the second fret while the first fret position is held by finger or capo. THAT DISTANCE, if created between the open string and the first fret, will theoretically still leave you a non-buzzing open string. This is how a zero fret works. Your nut can do the same.

    I'm hoping for commentary and competing theories to increase the overall user nowledge, including mine.
  2. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    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.

  3. edpal

    edpal Inactive

    Oct 3, 2007
    Alright! Sounds like a good way to check it too. Can't believe the instruments where that is more like .030+.

    And HAppy almost birthday!
  4. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician

    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.
  5. 96tbird

    96tbird PLEASE STAND BY

    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.
  6. walterw

    walterw Supportive Fender Commercial User

    Feb 20, 2009
    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.
  7. tylerwylie


    Jan 5, 2008
    Dunwoody, GA
    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.
  8. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    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.

  9. tylerwylie


    Jan 5, 2008
    Dunwoody, GA
    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.)
  10. iiipopes

    iiipopes Supporting Member

    May 4, 2009
    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.
  11. Hopkins

    Hopkins Supporting Member Commercial User

    Nov 17, 2010
    Houston Tx
    Owner/Builder @Hopkins Guitars
    This is basically how I do it.
  12. mongo2


    Feb 17, 2008
    Da Shaw
    I've found that OEM nut slots are always too high for my preferences so I adjust and ramp them accordingly.