Do I Need to Shim the Neck on My Bass

Discussion in 'Hardware, Setup & Repair [BG]' started by ryanhostetler, Dec 20, 2016.

  1. ryanhostetler


    Sep 15, 2016
    Denver, CO
    I've got a 2002 MIM P Bass that is in pristine condition. It looks almost new. I just swapped out the pickups and installed the vintage-style Fender bridge saddles. After I did so, I went about setting up the bass. I did a truss rod adjustment first, which I set to .015, and then I went to do the string height adjustment. I dropped the saddles VERY low and the strings are still too high. The E and G strings have the saddles dropped all the way so the screw hits the bridge plate and they're still to high. I'm thinking that I need to shim the neck or perhaps something else. What advice can you offer? (This was an issue before with the other saddles, although it didn't seem as prominent. Please help. This is a beautiful bass that I've put a lot of money into that I just have to get playing again!
  2. Well, it certainly can't hurt to give it a try! 1/2 an hour of your time could net you the bass you are hoping for!
  3. ryanhostetler


    Sep 15, 2016
    Denver, CO
    Is there an instructional thread for shimming? I've searched, but I haven't found exactly what I"m looking for. I'm pretty positive that I need to place the shim at the butt end of the neck pocket, but is there a science to how thick I go? I'm planning, as of now, to use a business card, probably doubled-up.
  4. bigtone23


    Dec 10, 2014
    Denver, CO
    It's your best option: shim away!
    I would do a single of the biz card at the body/butt end of the neck pocket first.
  5. k31bassman


    Feb 4, 2010
    A little can go a long way. Maybe just try one first.
    Fishheadjoe likes this.
  6. ryanhostetler likes this.
  7. MrMoonlight

    MrMoonlight Bottom feeder

    Sep 2, 2008
    I used a StewMac neck shim on a Telecaster guitar and it worked perfectly. Full contact between neck and body woods with no gaps...and I was able to set the guitar up exactly the way I wanted it. I suspect their bass versions will work just as well.

    They come in various sizes and tilt angles. Here's a video. They're a bit pricey, but they're an elegant solution that really works like a charm.

    Jeff Bonny likes this.
  8. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician
    A full-pocket tapered shim is not necessary. Theoretically a full pocket shim is better than a partial shim only because it leaves no gaps in the pocket. There is no evidence that an "air pocket" is detrimental in any way. There may even be an argument to the contrary. Think about chambered bodies....
    So start with a single layer of a business card extending from the but end of the pocket to just past the mounting screws on that end, the full width of the pocket. You'll probably find that's all you need. If you think that maybe a "cardboard" piece isn't good enough, use a piece of veneer, a bit of a beer can, a bit of plastic, whatever. It's easy, it's reversible, it's cheap and it's effective.

    If you are hung up about the "science of how thick I should go", I can work out a math formula for it, but it's not worth that amount of effort. Keep it simple - start with a single thickness of business card.
  9. ryanhostetler


    Sep 15, 2016
    Denver, CO
    I thought about these. The trouble was that I didn't know exactly what size I would need. The trial-and-error could get pretty pricey pretty quickly, not to mention the wait on shipping.

    I wasn't really looking for an exact science necessarily; I just wanted to know if there was one like there is with a lot of other setup stuff.

    I ended up starting with two pieces of a very thin business card. It seems to have done the trick on the first try. I'm pretty amazed at how such a little amount of shim could make such a significant difference.
    JLS likes this.
  10. JLS


    Sep 12, 2008
    eureka, ca
    I setup & repair guitars & basses
    I'm pretty amazed at how such a little amount of shim could make such a significant difference.

  11. dc-upright


    Mar 31, 2013
    I used the Stew Mac shim mentioned above with great success on a P with a Bad Ass bridge.
  12. mmbongo

    mmbongo I have too many basses. Supporting Member

    A little slice of sandpaper works great too, as it grabs onto the wood.
    Garret Graves and ryanhostetler like this.
  13. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician
    Very popular choice for a shim, but I've never understood it. Yes it grips - one one side. Doesn't on the other. So I'm not sure what the gain is.
    Geri O and ryanhostetler like this.
  14. mmbongo

    mmbongo I have too many basses. Supporting Member

    I put a little GlueStic on the other side.
  15. I'd first be sure I had removed enough relief from the neck; I would take it to almost level flat with only a slight amount of relief. I would then take a look at the nut slot depths to be sure they're not too high, that can have a bigger impact on action than some people realize.

    Of course, the flatter the neck, the more profound and noticeable un-level frets will become. If that's the case, I would have the frets leveled before I resorted to a shim.

    If attending to those things doesn't allow you to get your action low enough with simple saddle adjustments, then experimenting with a shim may be in order.

    I'm not down on shims, I've got one in a couple of basses and guitars, but I don't think we should jump to that remedy immediately without first attending to the other things I outlined. Going straight to the shim could also mask some more pertinent issues. I avoided shims many times by adjusting other details first.
    Last edited: Dec 24, 2016
  16. Hopkins

    Hopkins Supporting Member Commercial User

    Nov 17, 2010
    Houston Tx
    Owner/Builder @Hopkins Guitars
    I always have a few different grits of emery cloth on a roll on my work bench so its easy to tear off a piece for a shim. I never considered the abrasive aspect to be of any advantage.
    wcriley likes this.
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