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Truss rod instructions

Discussion in 'Hardware, Setup & Repair [BG]' started by Bass_masta16, Sep 1, 2008.

  1. Well, as you can probably already tell, I need truss rod instructions. :help:

    I have this old, walmart bass laying around, I have de-fretted it (myself, so yes, it does indeed look like crap :smug: ), and I want to lower the action.

    Now people on here tell me stuff about the truss rod, and then others tell me I can do it by the saddles ( they are currently as low as they can go) and the action at about 12 is atleast an inch+.. yes, you read correctly, an inch+.

    So I'm thinking the reason for the action being so utterly terrible, lies in the truss rod. (although I may be mistaken)

    Can anyone give me a basic step for step of how to adjust a tross rod so it could possibly help my action.

    Thanks for your time. And for the people who say that if I mess it up, it could wreck the neck.. I don't care if it does :p
  2. GlennW


    Sep 6, 2006
    Since it had frets I'd guess a major part the high action is a result of using the same nut. The nut slot height was set up to work with frets. You'll never get good action with high string height at the nut (frets or no frets).

    Make your current nut slots lower, or

    Remove the nut and take some off the bottom, or

    Get a new nut and start over.
  3. XylemBassGuitar

    XylemBassGuitar Supporting Member Commercial User

    Aug 14, 2008
    Durango, CO
    Owner and Operator, Xylem Handmade Basses and Guitars
    Hi Bass_masta16,

    Okay, this might be a long one because there are a lot of things going on here.

    First, I'll start with basics for properly adjusting truss rods:

    1) Tightening truss rods causes a backbow in the neck. That is, they cause the neck to bow away from the strings/counteract the pull of the strings. String cause a neck to upbow (also called relief).

    2) Before you adjust the truss rod, you'll want to read the relief on your bass to see which way you should adjust the rod. You can read the relief by looking at the side of the neck and fretting the low E string (and/or the G string) at the 1st fret and 12th frets simultaneously (you could also use the
    15th fret instead of the 12th), fretting the 1st fret with your left hand and the 12th/15th with your right. Now, look at how much space there is between the bottom of the string and the 6th/7th fret of the neck. The space between the string and fret is the relief. Generally, most basses and guitars operate best when there is about a business card's thickness of relief at the 6th/7th frets (but every instrument is different and there are exceptions).

    Thus, if your bass has more relief than a business card thickness, you'll probably want to tighten the truss rod.

    3) Before you tighten the rod: Always loosen the truss rod nut first as the nut may already be as tight as it can go; tightening the nut further may cause damage to the rod and potentially ruin the bass! Loosening just a little bit first will give you an idea of how tight the rod already is.

    4) Mark the adjustment nut with a marker to note where it started. Then, take the nut off the rod (keep track of how many turns it take to come off), clean and lubricate the threads of both the nut and the rod (3 in 1 oil works well). Be careful to keep the lubricant off the finish and wood.

    5) Put the nut back on the rod and turn it back to the mark (remember how many turns it took to take the rod off), this puts you back at the starting point.

    6) Tighten the rod only by 1/16 to 1/8 of a turn at a time, checking the relief of the bass in between each increment. If the rod already seems as tight as it will go dont' force it! you can break the rod this way.

    7) If you don't see any change in the relief after turning the nut a few 1/8 turn increments you should set the bass aside for a day or two an then re-check the relief. Some neck wood takes a little while to "settle" into the new rod tension.

    Keep this in mind while you are adjusting your truss rod:

    Adjusting truss rods does not lower the strings. Truss rods only change the bow of the neck. Tightening a truss rod can improve the action of an instrument, but it does so by taking out some of the relief, thus bending the neck closer to the strings; not by bringing the strings closer to the neck.

    Also, truss rods on cheap instruments do not always work that well. The rod may not be able to fix up the problem by itself. If you find yourself adjusting the rod fully without getting the desired effect, you can try this:

    Re-start from your beginning mark. Next, support the neck at either end and gently but firmly press on the back of it (basically, you are pushing out some of the relief with your own hand). While pressing on the neck in this manner, tighten the truss rod a bit. Doing this can sometimes help the truss rod "get started" and help it take out more neck relief.

    Now, let me ask: did you fill in the empty fret slots when you de-fretted the bass? If you did fill them, what did you use?

    I ask this because the fretboard imparts a lot of stability to the neck of the bass. If you didn't fill the slots or filled them with something that isn't very hard, you have effectively removed small portions of the fretboard that were helping to keep the neck straight under the pull of the strings.

    So, it would make perfect sense, in this case, that your action is very high because of a severe upbow (relief) in the neck caused by empty/soft fret slots. Thus, in your case, tightening the truss rod may very well improve your action (by bending the neck straighter, bringing it closer to the strings).

    BUT, keep what GlennW says about the nut in mind as well.

    If you're not comfortable making changes to the nut by yourself, take the bass to a repair tech or luthier, they should be able to lower it properly.

    If you want to make modifications to the nut yourself, here is a quick guide:

    You can remove the nut by placing a block of wood against the fretboard-side of the nut and tapping the wood with a hammer (hopefully the manufacturer didn't use too much glue when fastening the nut down).You may want to remove the nut and sand it down on the underside (if you do this yourself, make sure to keep it square and flat!). You can keep the nut square and flat by putting a piece of sandpaper on a flat surface and placing a piece of wood with a flat/straight side on the sandpaper so that there is a perfect right angle formed between the wood and sandpaper. Now hold the side of the nut against the piece of the wood while you sand the bottom, this will keep the bottom of the nut flat and the side that faces the fretboard square with the bottom.

    Don't sand away too much of the nut, you may have to get a new nut if you do. A little sanding can go a long way to improving the action. When you have lowered the nut, test it out on the bass without glue to check if it's the right height. When you are ready to glue down the nut, only use a small drop or two of glue. You could use hide glue, Elmer's carpenter's glue, Titebond, or even white Elmer's, the glue is just there to keep the nut from falling off when you remove the strings. Then allow the glue to dry (you can use the strings as clamping pressure for the nut if you are sure that it doesn't move when you bring them up to pitch).

    Again, there are a lot of factors here and I can't guarantee that what I have recommended will fix the bass without actually seeing it in person; so try this stuff at your own risk.

    But, if you have any questions or need clarification let me know.

    Good luck.
  4. Wow

    Thats all I have to say

    Thank you very much for taking that time to write all that
    And you aswell GlennW
  5. XylemBassGuitar

    XylemBassGuitar Supporting Member Commercial User

    Aug 14, 2008
    Durango, CO
    Owner and Operator, Xylem Handmade Basses and Guitars
    Sure, glad to help!

    Let me know if you run into any snags and/or how the adjustments to the bass turn out.

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