Full pocket shims vs Back of pocket shims

Discussion in 'Hardware, Setup & Repair [BG]' started by AdmiralBumblebe, Jun 3, 2020.

  1. I've always made full pocket shims, because...

    • I've seen 2 older fender bolt-ons with shimstock in the back of the neck pocket that made an indent in the pocket over time.
    • I've seen multiple instruments with 'cave in' between the shim and the sole body/neck joint. Required fret work and left an ugly slightly curved neck/body joint.
    • Seen one instrument with fret sprout right above the shim, shortly after shimming.
    • As per "common sense" I have an unsubstantiated dislike of not having full contact across the joint for tone reasons.
    So where the question comes in is that I have 2 bolt-ons that need shimming and rather than walking over to my shop I decided to contact the manufacturers.

    Both manufacturers offer, and shim from the factory, with thin shims that sit in the back of the pocket or over the last 2 screws. These are not cheap instruments.

    The whole micro-tilt system further places doubt on my preference of full shims.

    Curious about opinions from people with strong opinions.
    Last edited: Jun 3, 2020
  2. JRA

    JRA my words = opinion Gold Supporting Member

    my exceptionally strong opinion ( :D ) is that almost any shim works if the bolts can hold the neck and body tightly enough, together. a strong, tight mating of neck and body is the ticket to not having tonal/other issues.

    most folks who use shims don't report problems. some axes just need shims. (i use back-of-pocket shims.)

    good luck with your shimming quest! :thumbsup:
    DrMole likes this.
  3. I’ve used both. Usually I only make a full size tapered shim if i need a larger angle, for instance mounting a Bigsby on a Telecaster and using the Jaguar bridge. For most typical applications a shim at the front edge of the pocket is fine.

    Also, if you’re interested, here’s a pretty lengthy discussion about partial shims and whether or not they cause ski jumps.

    Getting the Facts about Ski Jumps
    dwizum likes this.
  4. Doner Designs

    Doner Designs Steve Doner Gold Supporting Member

    Jun 2, 2012
    Metro Chicago Area
    Doner Designs is an alias for Steve Doner
    I never use a shim unless the bridge saddles won't go low enough. In that situation I make a shim that fills the entire pocket so the neck stays flat. I really don't understand the concept of a tilted neck and why you would want that. I've never seen a setup issue (except in a defective/warped neck) that can't be solved in the normal way with truss rod or bridge saddles. I would only go to a shim (and a flat shim in that case) when one or more bridge saddles are all the way down. Professional luthiers may be able to shed more light.
  5. Nashrakh


    Aug 16, 2008
    Hamburg, Germany
    I've only onced needed a full pocket shim. That was for my Ibanez SR which has a highly asymmetrical neck pocket and screw alingment. The usual didn't quite work as intended.

    But for my Fender... The tried and true. Never noticed a change in tone in any shim scenario encountered.
  6. No more saddle movement is the situation I'm solving.

    The neck pocket is slightly sloped inwards (checked with dial indicator relative to body).

    Tapered shim is the most reasonable fix for this that I'm aware of.
  7. johnson79


    Jan 8, 2010
    Lancaster, PA
    I just put on a new Mighty Mite neck and the action is ridiculously high. Need to tinker and probably add a shim. How does one go about making a full pocket tapered shim with basic shop tools? Can I do it with a miter saw?
  8. bassdude51

    bassdude51 "You never even called me by my name." Supporting Member

    Nov 1, 2008
    Central Ohio
    Stew Mac has wonderful full pocket shims with angles or flat.

    s-l400.jpg StewMac Neck Shims for Guitar | stewmac.com

    guitar neck shims | eBay

    And yes! You are right, go full pocket shim.

    I have a 1966 Fender P Bass and when I popped off the neck there was one of those little shims at the very end of the pocket. I took it out. It was not even needed. I heard that Fender many times stuck in shims whether needed or not. I sold the damn shim on eBay for about $28.
    Last edited: Jan 6, 2021
    BLDavis likes this.
  9. Arie X

    Arie X

    Oct 19, 2015
    i like a full shim -it feeds my craftmanship ocd.

    otoh, i've seen a lot of fabricky tape nubs on new instruments.
  10. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician - Retired
    First off, shims don't cause ski jumps. If you want to hear more about it, check this thread where a number of professional repair techs chime in:

    Getting the Facts about Ski Jumps

    Secondly a shim cannot cause fret sprout.

    A partial pocket shim works fine and without causing problems. But it should be done right. Make sure the shim extends just past the inner screw holes as in the second example., not like the first:

    PArtial Shim.jpg
  11. 96tbird

    96tbird PLEASE STAND BY

    I partially shim in the anonymity and security of my own home.

    I am not ashamed of it no matter what the full pocketists cry.:roflmao:
  12. dwizum


    Dec 21, 2018
    I've done both, many times. I don't see any indication that partial shims cause any specific issues. I know some people see issues on necks that happen to have partial shims, but those issues also appear on necks with no shims at all - I'm not sure it's appropriate to assume causation.
    wcriley likes this.
  13. Mili


    Nov 14, 2015
  14. Arie X

    Arie X

    Oct 19, 2015
    on new sub 1k instruments, it's not uncommon to see a hunk of tape at the back end of a neck pocket. i do like to see tight contact with the pocket floor rather then an air gap, sawdust, lumpy paint, buffing compound, and chips stripped out from the neck screw holes though.
    Last edited: Jan 7, 2021