Shim ideas for fitting loose Underwood pickup

Discussion in 'Setup & Repair [DB]' started by mav, May 5, 2018.

  1. mav


    Jun 10, 2003
    The bridge wing gap is too wide for my Underwood pickup, need to shim it up with wood or something else someone might recommend.
  2. shwashwa


    Aug 30, 2003
    Try different things as they affect the tone. Fold up some paper, use a business card. I used to enjoy the damping qualities of paper when shimming other Wing pickups
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  3. salcott

    salcott Supporting Member

    Aug 22, 2007
    NYC, Inwood.
    Sax or clarinet reed. Shove it in (not at the wing side), break it off.
  4. mdcbass


    Feb 6, 2005
    Seacoast of NH
    I think the Underwood supplied shims may have been balsa wood.
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  5. Eric Hochberg

    Eric Hochberg

    Jul 7, 2004
    A slice of cork works too.
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  6. Don Kasper

    Don Kasper Gold Supporting Member

    Underwood provides card stock for shims. See below.
    Hobby shops sell very thin (1/16in.) plywood which is very rigid and consistent.

    Last edited: May 5, 2018
    mav likes this.
  7. mdcbass


    Feb 6, 2005
    Seacoast of NH
    When I bought the Underwood, it came with the wood shims (and an RCA jack) but that was a long time ago. In any case, paper is (or used to be) made from wood pulp so it's all good.
  8. HateyMcAmp


    Apr 13, 2006
    Queen City of the Plains
    Krivo Pickups
    I always used a heavyweight business card for my bridge wing pickups.
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  9. Paper is made from wood, but it might behave differently. It depends on the amount of compression the paper or cardboard got during production how much vibration might be absorbed by it.
    On the other hand, it is always possible to push the cardboard with a hammer before cutting it out so that would be a good amount of compression.
  10. RSBBass


    Jun 11, 2011
    I don't use an Underwood but have used cork to good effect on my Schectler (SP?). Being in the wine sales business I have a good supply.
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  11. M Underwood

    M Underwood Guest Commercial User

    Aug 30, 2017
    Head of Operations, Underwood Pickups
    Hi all,

    We at Underwood recommend using card stock as shims. Although sax reeds sound like a cool idea! One benefit to using cardstock is that it absorbs very little, if any, moisture from humidity, and therefore will not contribute to increased pressure on the pickup when you move your bass from one situation to another- for example if you live in Alabama and are transporting your bass to an air conditioned gig. Humid to dry air. The bridge, obviously made of wood, will swell and shrink, quicker than you may think, and that increased size means increased pressure on the pickup. I'd say most of our inquiries for repair have to do with this very situation. The transducers are highly subject to breakage from excessive pressure. Making sure the installation is not too tight is key. Never force it in. Our recommended fit is a lot looser than you'd think. Just enough to keep it from falling out during transport or play. So check your pickup's fit all the time, use cardstock for shims and let us know if you have any questions.
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