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Gibson 2-point tuneomatic bridge

Discussion in 'Luthier's Corner' started by nbfanc, Nov 14, 2005.

  1. nbfanc


    Nov 12, 2005
    I am finishing a restoration of a 1971 Gibson EB3L. But I cannot figure out how to get the bridge to sit flat against the body. When the strings are up to pitch, the back of the bridge angles up, making the action terribly high. What's the secret to making this guy work?

    The bridge attached to two adjustable height posts. Two small allen set screws tighten the bridge to the posts and seem to be the only things that resist the upward pull of the strings on the back of the bridge.

    I attach a picture to ditinguish this bridge from other Gibson bridges.

    When I got the bass, it was in pieces, (and missing several of them), and I have no example to work from.

    Attached Files:

  2. MPU


    Sep 21, 2004
    Valkeala Finland
    Did you ask from thedudepit.com? There's a discussion board for Gibson basses. I've found out that the guys there have a lot of knowledge about Gibsons.
  3. nbfanc


    Nov 12, 2005
  4. Giraffe

    Giraffe Supporting Member

    Nov 6, 2003
    San Diego, California
    I spent a lot of time messing with these bridges when I was on my Gibson kick. One problem they had when engineering that unit was building enough slop into the vertical holes to allow the bridge to be adjusted into positions other than perfectly level from the bass side to the treble side. If they machine those two holes to a very tight tolerance, you can't set the bass side higher or lower than the treble side because the posts would bind in the holes. They machine those holes oversize, and you use the set screws to take up the slack after you get it adjusted where you want it. The set screws were never able to move that bridge into the level position while under string tension, hence the three-point solution.

    The best solution I could come up with was to first remove the factory set screws and replace them with new stainless steel screws the same length as the channel they travel in. This seems to give them a little more purchase on that somewhat soft casting, and seems to let them apply more tension on the posts when you torque them down. I would then remove or at least completely slacken the strings to remove the tension that tilts the bridge base forward. Next I adjust the posts a little lower than you would assuming the bridge was not going to tilt. (There may be a little trial and error needed here.) Then crank the set screws down as tight as you can safely get them.

    Now tune it up. The bridge will still tilt a little bit, but not as much as if you adjusted the post height with the set screws backed out and the strings tuned to pitch. The set screws are not strong enough to force the base flat once you are tuned to pitch, but they can do a decent enough job of holding it somewhat level if you tighten them down before the strings start tilting the base up. Once you get the thing adjusted to where you want it, it will stay in place through subsequent string changes. Not perfect, but close enough for most players.