Truss-rod: clearance

Discussion in 'Hardware, Setup & Repair [BG]' started by Boneless, Jan 19, 2022.

  1. Now, there is a lot of conflicting info on how to adjust a truss-rod. Assuming that you observe clearance at the 8th fret while depressing at the first and last fret, I've always gone for 0.7-0.8mm. Others say 0.3mm while pressing at the first and 15th (makes sense, that's where the truss rod acts after all, if you measure at the last fret you have to account for the last frets, ie. a longer arc). Some luthier, whom I can't find any more, said that anything between 0.3mm and 1mm (measuring at first and last) is OK, with more bow actually beneficial for lower actions. I'm stumped. To be honest, what I do is generally set up the bass until it plays with only a bit of fret noise if I play hard, but I'd like some more precise information in order to avoid damaging stuff (keeping a neck too bowed in the long term may make it impossible to straighten it, perhaps?).
  2. Spidey2112


    Aug 3, 2016
    At all costs, do no spill hot coffee on your jumblies.

    (Sounds like got a handle on making a successful truss rod adjustment... carry on.)
    Boneless and Zooberwerx like this.
  3. vaesto


    Jun 21, 2010
    String needs space to vibrate. It is achieved by combination of action and neck relief. It is only who can say which proportion is good for you, wherefore, there are no "exact" specs for setup, just general guidance to follow.
    Flat neck + high action will result in more buzz on lower frets while "too high" feeling on upper ones.
    To much bow + low action - all reverse - it will be more comfortable on lover frets, but will result in buzz on upper ones.
    It takes some time to find that "golden mixture" of relief and action. Though, NEVER adjust the string height by altering relief.

    You won't damage any stuff by setup unless it passes way beyond what we consider "normal". But, if setup is off - then I doubt the bass will be comfortable to play.

    What you shouldn't do is leave TR engaged while stings are off for a longer time (or wise versa), but this more about storing bass/neck for a longer periods of time.

    Also, keep in mind the wood is not plastic or metal. It may change with time and develop various "illnesses". These are rarely related to bad setup, just matters of nature.
    Boneless likes this.
  4. 96tbird

    96tbird PLEASE STAND BY

    Keeping neck relief where it is satisfactory (needs to be) for you to comfortably play will never cause damage. This is because anyone that can play a bass with even a modicum of competence wouldn’t stand for a neck that is so drastically bowed that it is in jeopardy of becoming permanently damaged.

    it would feel horrible to play and perform poorly and you’d be seeking professional assistance in getting it into trim.
    Boneless and Justinian like this.
  5. Arie X

    Arie X

    Oct 19, 2015
    yeah, there is a lot of conflicting "info" so why not bypass all of that and grasp the core concept of what is going on with strings and necks and how to make all of that work for you?.

    it's called string excursion. understand this, and the rest will fall into place. :)
  6. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician
    1. It is possible to set up a bass with a truly flat fretboard, but it won't be optimum. A truly flat fretboard will not endanger the neck at all.
    2. If you want the action to be as low as possible, all adjustments will be dependant upon how you play - you pluck hard or lightly, you tend to strike the strings rather than finger them, your fingers are at right angles to the strings or oblique to them, you play closer to the bridge or closer to the neck, etc.
    3. For optimum performance, you will need to find the adjustments that work for your playing style by trial and error.
    4. Measuring relief is best done between the first fret and the fret at the body joint of the instrument, otherwise your measurements will be confounded by any ski jump effect. Since the truss rod cannot affect the neck curvature beyond the body joint, any attempt to correct for apparent excessive relief when measuring end-to-end may well be counter-productive. It may introduce further complications such as the "dreaded S curve".
    5. Use relief to control the string buzz at the first three frets. Use the bridge height to control fret buzz above the body joint.
    6. Be systematic. Understand what each adjustment is doing. Make one adjustment at a time and evaluate its effect.
  7. testing1two

    testing1two Supporting Member

    Feb 25, 2009
    Southern California
    +1 to the above.

    One more consideration to add to the mix: relief is often blamed [and subsequently fussed with] for all sorts of things with when the real culprit is a deformed neck and/or un-level frets. Granted these are much more difficult things to correct, but if you have a true neck and level frets, the range of acceptable neck relief is much broader.
  8. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

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