The Jazz Guitar Chord Dictionary
  1. #1

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    Hello there. I am a new owner of an Ibanez GB10se, my first archtop ever, which has a traditional all wood floating bridge with thumb wheels. I have had it professionally set up for my choice of strings.

    Can you educate me as to the function of the bridge thumb wheels? What are they for? How would one make an adjustments with them and for what purpose? How can one get into trouble using them?

    Thanks for bringing up "Junior"!


  2.  

    The Jazz Guitar Chord Dictionary
     
  3. #2

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    allow you to adjust the string height to your preference
    turn them clockwise and the strings get closer to the fingerboard, counter to raise them.

  4. #3

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    If your action is too high, strings too far above the frets, you can lower them by turning the wheel, or wheels, depending on whether both sides need adjustment, clockwise as seen from above with the guitar horizontal. If the strings are too low, giving fret buzz and/or poor tone, you can raise them by turning the wheel(s) the other way. You may be able to do it by finger pressure, but if not there are tools that. A standard pair of pliers will work in a pinch, but it's not my preference. I generally use a bridge jack, which is a lever with the end bent to give it purchase for prying up the saddle. I insert it into the gap between the base and the saddle. Stew-Mac sells them, for more than $50. Tune-o-Medic Bridge and Tailpiece Tools - StewMac
    I made mine from a freebie paint can opener from the local home improvement store, and it works just as well. You can get a spanner wrench from StewMac, or from ebay, that will also work, and do other guitar jobs. Ebay is many times cheaper, and again work as well.

  5. #4

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    you don’t actually NEED tools to
    adjust the action (string height)

    first .....
    mark where the bridge base is
    with tape (or a felt tip pen if you don’t
    mind writing on your guitar .... I don’t)

    because it may move about a bit
    with the following procedure

    then slacken off strings a bit to take
    the tension off the bridge

    adjust half a turn whichever way you want
    up or down (anti clockwise or clockwise)

    tune up , check the playing feel
    (string height or ‘action’)

    repeat the above till you
    get the action to your taste

    simples !

  6. #5

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    They're a feature that goes hand in hand with archtops. Archtop guitars, unlike the history of guitar prior to the 20th century are made more in line with violin construction practices than flat top guitars (flat piece of wood braced for strength). Much of the strength of the archtop comes from the downward pressure of the bridge sitting on an arched structure (picture a bent piece of paper as opposed to a flat one). This let the top be tuned and the top to have an evenness of sound but it also made the arch height vulnerable to changes in weather. Top absorbs moisture, the wood expands, the arch increases and the top goes up raising the action.
    For a good playing guitar, increments of fractions of a mm can be felt. So as the arched top "breathes" seasonally, the thumb wheels allow you to maintain the same action you need even as the top beneath the strings changes.
    There's a little information so you can feel a little closer to your new guitar. That's a beautiful guitar. Play it and love it.
    By the way, the laminate construction of your top will make it less subject to seasonal change but it's still great to be able to change your action easily.

  7. #6

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    Archtop Setup

    FRETS.COM

  8. #7
    Quote Originally Posted by Jimmy blue note
    They're a feature that goes hand in hand with archtops. Archtop guitars, unlike the history of guitar prior to the 20th century are made more in line with violin construction practices than flat top guitars (flat piece of wood braced for strength). Much of the strength of the archtop comes from the downward pressure of the bridge sitting on an arched structure (picture a bent piece of paper as opposed to a flat one). This let the top be tuned and the top to have an evenness of sound but it also made the arch height vulnerable to changes in weather. Top absorbs moisture, the wood expands, the arch increases and the top goes up raising the action.
    For a good playing guitar, increments of fractions of a mm can be felt. So as the arched top "breathes" seasonally, the thumb wheels allow you to maintain the same action you need even as the top beneath the strings changes.
    There's a little information so you can feel a little closer to your new guitar. That's a beautiful guitar. Play it and love it.
    By the way, the laminate construction of your top will make it less subject to seasonal change but it's still great to be able to change your action easily.
    Oh this was so interesting. Thank you for that orientation!

  9. #8
    Quote Originally Posted by rob taft
    Archtop Setup

    FRETS.COM
    Great pictures; thanks