how many turns on a truss rod?

Discussion in 'Hardware, Setup & Repair [BG]' started by ics1974, Nov 9, 2012.

  1. ics1974


    Apr 13, 2012
    When I bought my MIM Fender P-Bass the neck was really bowed. I have it pretty straight now by turning the truss rod a 1/4 turn at a time but I have turned it at least two full turns now. I am just wondering how I know if I tighten it to it's max. Will it just stop turning or will it break before I get a warning?
  2. Dave W

    Dave W Supporting Member

    Mar 1, 2007
    White Plains

    It shouldn't break, it's a nut on a threaded rod. Just be gentle when making adjustments.
  3. Pilgrim

    Pilgrim Supporting Member

    Be gentle and wait at least a few hours in between adjustments. It can take time to get it right, and the neck doesn't respond instantly.
  4. 1/4 turn at a time is best. Loosen the strings before hand. The neck
    will respond better with no string tension holding it back..

    Right turn to get rid of bow/relief.
    Left turn to get rid of back bow. (I don't usually loosen strings for this)
  5. SpinyNorman


    Oct 24, 2012
    I understand this is how it works, but it does seem counter-intuitive. Generally speaking, turning a screw clockwise draws it in, which would cause the bow to increase.

    Any idea why truss rods work the other way?
  6. I am ultra-cautious, so I sometimes go 1/4 turn per day.

    And yes, when the rod is maxxed, it simply won't turn any more without incredible force, at which point it will probably break. It may have been very loose from the factory or incompetence, and a couple of full turns is not out of the question, as long as you are seeing the relief change as you turn.
  7. Bassist4Eris

    Bassist4Eris Frat-Pack Sympathizer

    Aug 11, 2012
    Upstate NY, USA
    The bowing is caused by the tension of the strings. The truss rod pulls against this tension. So when you loosen the truss rod, the strings pull harder on the neck, causing increased forward bow, and when you tighten, the truss rod pulls harder against the strings, causing the neck to straighten.
  8. ics1974


    Apr 13, 2012
    ok thanks guys. So just to be clear the only way to break the rod is to run out of threads and crank on it till it breaks?
    I was worried it would somehow break before you run out of theads, without using allot of force.
  9. Dave W

    Dave W Supporting Member

    Mar 1, 2007
    White Plains
    It depends how the rod is made. It can certainly break at other points than just at the nut/threaded end.
  10. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    either way, it's a steel rod; you're not gonna break it without applying real force.

    as for this "1/4 turn, wait a day" nonsense, it's, well, nonsense.

    tighten it until you get the neck where you want it, then get on with your day.

    if it starts to get really hard to turn before you get where you want, especially if you feel it sort of twist, then untwist when you let go, that's the time to start worrying.

    even then, there are tricks for that, from removing the nut to lube it up, to clamping the neck into backbow first, and other things.
  11. Lemon Of Troy

    Lemon Of Troy Banned

    Nov 6, 2012
    Palmetto State
    Yeah all of my basses respond instantly to the trussrod adjustment, I can really fine tune the action. These are higher end basses though, not sure if that matters. Never had a Fender.
  12. 96tbird

    96tbird PLEASE STAND BY Supporting Member

    To answer why tightening works as you say, "in reverse"". The rod sits in a curved channel: close to the fretboard at both ends and close to the back of the neck in the middle. You tighten the nut, the rod exerts force on the middle of the the neck channel and bends the neck back straight.

    Walter is right: nonsense. Physics. The force exerted by the rod pushes the middle of the neck out. There's no such thing as the wood settling. Not just nonsense; it approaches the ridiculous.
  13. fourstringdrums

    fourstringdrums Decidedly Indecisive Supporting Member

    Oct 20, 2002
    On my Fender and honestly on just about every bass I've ever owned, the truss rod responds pretty much instantly. I think when people say to wait a day that's more to see if the neck keeps moving.
  14. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    sometimes if you've had to crank it up a lot, you might get a slight "overshoot" a little while later, where it goes just a little further than you wanted.

    if that happens, you just loosen it a pinch (and then get on with your day :)).
  15. FerK

    FerK Supporting Member

    Dec 11, 2011
    I would imagine that if you use a regular hex Allen wrench you shouldn't be able to break the rod, would you ? I mean...the wrench is a lot smaller than the rods thinnest cross-section. In the worst case you might manage to damage the rod's end, where the wrench connects. Is that right ?
  16. Dave W

    Dave W Supporting Member

    Mar 1, 2007
    White Plains
    Nope, people break them all the time. It depends how the rod is made.

    Not that it has anything to do with it, but depending on the rod, the allen wrench can be larger than the diameter of the rod.
  17. Stilettoprefer


    Nov 26, 2010
    A big +1.

    They're more fragile than you think. A good thing to do when tightening the rod is to physically bend the neck back while you turn the wrench. This takes a lot of pressure off of the nut and will greatly reduce your chances of screwing something up.

    And this 1/4 turn a day thing is total BS. It's just a waste of time. I have turned rods 3 whole turns within 15 minutes before and have never had problems or have a neck need a period of recovery.

    How do you think they do it at the factory? They're not gonna have guitars sitting around for a month just to get the neck set.
  18. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    nope, because with standard rods the allen wrench is going into a big cylindrical nut that's screwed onto the rod. the rod doesn't spin, the nut just tightens down onto its threaded end.

    with the exactly right-sized wrench (so it fit the hole cleanly), you could indeed break the rod if you tried hard enough.

    it does take real force, though; a properly-working neck will be cranked into huge backbow way before you get to the point of risking anything like this.
  19. +1, this is what I meant.