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Neck Shim for lowered action?

Discussion in 'Hardware, Setup & Repair [BG]' started by chutsk10, Jul 20, 2007.

  1. I recently defretted a Jazz Bass and now I find I can;t lower the action enarly enough, my saddles are as low as can go and I've got nearly a cm height at the 12th fret.

    I think i read somewhere a shim can be used somewhere on the neck, does anyone know of this procedure?

    Is there any other way to lower the action in my case?
  2. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Ya, you can take a very thin piece of shimming material (broken single edge razor blades are my favorite, or you can use a matchbook cover or a thin piece of wood), and put it in the base of the neck pocket.
  3. louieeadg

    louieeadg uncle petey?

    Jun 13, 2007
    outer banks, nc
    STOP WHAT YOU'RE DOING!!! Now, while what the other post said is TRUE about making a shim. That's not what you need my friend. I've converted 2 basses from fretted to fretless and the same thing happened to me the first time I did it. All you need to do is loosen the neck. When you take frets out of a bass you weaken the neck. That's why Jaco epoxied his fretboard, to make it stronger. Just loosen your neck, and make sure you use some really good wood glue on those lines where the fret used to be! You don't have to epoxy it but it will make the neck stronger. And unless its your el cheapo bass you absolutely don't care about, use flatwounds or tapewounds on it so you don't eat the wood on the neck...

    Just speaking from experience,
  4. Yeah I've got flatwounds, and as for the neck, i filled the slots with a maple vaneer and used good wood glue, the neck itself turned out wonderous it's just the action whihc buggs me.

    So you say all I have to do is loosen the neck? as in the truss rod, or where the neck bolts to the body?

    As for weakenign the neck, I wouldn't imagine removing the frets makign it that much weaker... and isn't epoxy generally used to harden up the neck so roundwounds can be used withoguth eating up the board, not so much for strength?
    Anyway strength is nt an issue, its just the action, I will try loosen the neck and see what happens.

    Attached Files:

  5. louieeadg

    louieeadg uncle petey?

    Jun 13, 2007
    outer banks, nc
    Yeah, loosen the neck at the truss-rod. That's why you're action's so high. 1/8 of a turn at a time.

    And yeah, the epoxy was for the roundwounds.

    Looks good though! Hope you enjoy your "new" bass...


    what kind of Rick do you have?
  6. Dan1099

    Dan1099 Dumbing My Process Down

    Aug 7, 2004
    Don't just go loosening the neck all willy-nilly. You need to appropriately set the relief. There should be about a business card worth of gap between the string and the neck at the middle of the neck, when you hold down the first and last positions. Once this is set, you MAY need to shim it.

    When I defretted my bass, it did need a shim, and a new nut cut.
  7. remember, action begins at the nut...

    you've defretted...have you done anything about the nut?
  8. louieeadg

    louieeadg uncle petey?

    Jun 13, 2007
    outer banks, nc
    That's awesome.

    I was just telling him to first try loosening a bit before trying a shim to take a tiny bit of tension off the neck and that might get his action situation settled. Once that's done and he's still not satisfied with the action, then he should play with the nut....
  9. 202dy

    202dy Supporting Member

    Sep 26, 2006
    From the information you have provided it is impossible to render a semi-accurate diagnosis. The first, and most important piece of information is relief. How much relief is in the neck? The next bit of information needed is string height at the twelfth fret both bass and treble sides. Make the measurements and post them here and someone will be able to guide you through the process.

    Loosening the truss rod will provide more relief and the strings will be further from the fretboard.

    Loosening the neck bolts and tilting the neck accomplishes the same thing as shimming except that the connection is not a stable one nor is energy transfer as solid.

    An epoxy finish on a fret board is merely a finish. The film offers no structural integrity to the assembly whatsoever.
  10. gjooro


    Mar 27, 2006
    Jaco epoxied his FB so the rounds dont damage it, not to make it stronger. The strenght is in the neck and truss rod, but other you said is correct, just loosen the truss rod.

    This is great tutorial for adjusting truss rod:
  11. louieeadg

    louieeadg uncle petey?

    Jun 13, 2007
    outer banks, nc
    Yeah, I gotcha. I was more aimed at saying the epoxy would make the surface of the neck stronger. I wasn't clear. Plus I wrote that last night after a few pints...
  12. pkr2


    Apr 28, 2000
    coastal N.C.

    IMHO about the worst mistake that anyone can make is to start making adjustments in hopes that the problem will go away when you don't understand the mechanics of each adjustment.

    As a "for instance", if your action is too low, adjusting either the truss rod or the saddle height can result in the strings being further from the fretboard. The problems start surfacing when the root of the problem is a misadjusted saddle but the truss rod is adjusted and the problem appears to get better.

    The problem then changes from a bass with only one problem to one with two problems. The original problem plus the problem that has been introduced by the erroneous adjustment.

    The error can multiply (and often does) by the introduction of still another misadjustment, such as shimming the neck when the original correct remedy would have been a simple bridge adjustment.

    The various setup adjustments can be a powerful diagnostic tool in the right hands. In the wrong hands, propelled by well intended misinformation, the can become a recipe for failure and possible disaster.

    It can't be emphasized too strongly that the setup must be done in the proper order or the result will be doomed to failure from the gitgo.

    The whole geometry of a proper setup is based on a properly adjusted truss rod. Until that is achieved, the end result will be a less than good, to an unplayable setup.

    Don't ask me how anyone can know whether any particular advice is being offered by an expert at setup or by someone who may know less than the person who is asking for help. The only defense against poor advice on a forum are the members who do have the experience pointing out the misleading and bad advice offered by someone who may be less skilled.

    This invariably leads to bickering about who's right and who's wrong, with the person who needs help left holding the short end of the stick.

    Rather taking this thread even further off topic (my apology to the OP), I am going to start a new thread asking for suggestions on alleviating an ongoing problem that has plagued this forum for years.
  13. louieeadg

    louieeadg uncle petey?

    Jun 13, 2007
    outer banks, nc
  14. It's a 2006, 4003 Jetglo (More or less Geddy Lee Inspired, I am still looking for a 1972 4001 Jetglo)

    And I actually defretted my jazz to justify buying a Geddy Jazz (I couldn't have two fretted jazzes) not because I am obsessed with him but because i finally played one and loved it.

    As for the set-up, people asked about the Nut, Yes I have filed it down. Althoguh the first defret I've done I tried to do it as "right" as one could by following a wack of internet sugestions.

    I will probably end up taking it in somewhere to get it professionlly set-up since I was never good at it. I was just more or less wondering wht this "shimming" was about and now I kind of know.
  15. louieeadg

    louieeadg uncle petey?

    Jun 13, 2007
    outer banks, nc
    Ah, sweet ric. I have a 75 fretless 4003.

    Hope you got what you were looking for.
  16. Dan1099

    Dan1099 Dumbing My Process Down

    Aug 7, 2004
    Proper order is always Truss Rod first, Saddle Height second, Intonation Third. TUNE REGULARLY throughout the process. If you have set all three to your liking, and it still won't go low enough for you, at this point looking at shimming the neck is worthwhile. Also, if first position is high, but putting a capo there makes the rest of the neck great, you might need to bring the nut down.
  17. Just completed all that and it worked out well, I actually lowered the slot in the saddle a bit too, it is a brand new Badass 2 and I figgured I didn't lower them low enough in the first place.

    All is well, Still would like the action a little lower but it's not worth screwing with a shim.

    Just a thoguht, when you adjust the truss rod first, and then move the saddles around, you are changing the string tension so does that not in turn again screw with the truss rod?
  18. Dan1099

    Dan1099 Dumbing My Process Down

    Aug 7, 2004
    That's why you always retune after every adjustment. Also, if you want to get really nitpicky, perform all measurements with the bass in playing position.
  19. Dan1099

    Dan1099 Dumbing My Process Down

    Aug 7, 2004
    +1. There's no "Finished" perfect setup. It's an iterative procedure, and when one thing throws another out of whack, it's okay. You just keep going, and eventually center in on where you need to be.
  20. 202dy

    202dy Supporting Member

    Sep 26, 2006
    All measurements and setups are to be done in playing position. Any adjustments made in the work position are subject to change when the instrument is held in playing position. Playing position allows the tech to make the adjustments accurately. It is not picking nits. It is essential to performing a correct setup. It is one of the differences between the dilettante and the professional.

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