acoustic bass pins slips out

Discussion in 'Hardware, Setup & Repair [BG]' started by Listetyven, Apr 22, 2012.

  1. Listetyven


    Feb 23, 2009
    I have a Harley benton acoustic bass and the pins holding the A and E strings in place is working themselves out as I use the bass.

    Anyone know of a way to make these stay put? :)
  2. Slowgypsy

    Slowgypsy 4 Fretless Strings

    Dec 12, 2006
    NY & MA
    Stringing an ABG with bridge pins is the same as stringing a 6-string guitar.

    What's happening with your instrument is the string ball is not ending up on the side of the pin but locating itself underneath the pin. When it's underneath the pin it gradually pushes the pin up.

    Here's a link to stringing a 6-string guitar, the process for you is the same: Restringing - Steel Strings
  3. 202dy

    202dy Supporting Member

    Sep 26, 2006
    Good link.

    Incorrectly installing the strings so that the ball engages the bottom of the pin causes the pins to rise. Then the pins are pushed back in with more effort in an attempt to hold the string in tighter. If done hard enough and often, a crack will open up and connect the pin holes along a grain line.

    This activity is the number one cause of a split in the bridge.
  4. hi.

    Here's a few more pics about what we're talking about:



    Not my pics, just found 'em with Google when this same exact question was asked the last time.

  5. Listetyven


    Feb 23, 2009
    Thanks for the replies!

    I just took out the strings to make sure they were correctly installed, and so they seemed to be. They are installed they same way as the other two strings, so I'm guessing It's the high tension on the A and E string causing the problem.

    This particular instrument is the fourth I've had in my possession; the preceding basses were all damaged when I received them, and I noticed the problem on all of them.

    Since the back n' forth commotion with the dealer, who shall remain unnamed, is getting old I am left with fixing it myself.

    Soo.. any suggestions? :)
  6. 202dy

    202dy Supporting Member

    Sep 26, 2006
    Check to make sure that the ball end is firmly positioned against the bridge plate (sometimes known as the bridge pad). That is the piece of wood that is glued to the top in T-Bird's excellent photograph. Note that the grain is running perpendicular to the grain in the top. The bridge plate adds considerable stiffness to the top. It helps to prevent the top from developing a belly between the sound hole and the bridge. If the ball end is not firmly engaged or there is slack stored between the ball end/plate junction and the bridge pin holes, the bridge pins will continue to rise during tuning. It is essentially the same problem. Eliminate that (too) and the string will become stable.

    As an aside, in theory one should be able to remove the bridge pins and play the instrument while it remains in tune. It does not always work this way in practice.
  7. JTE

    JTE Gold Supporting Member

    Mar 12, 2008
    Central Illinois, USA
    The ball ends need to be against the bridge plate, and the grooves in the pins need to be against the strings. It's not tension that's causing your E and A to come out at all. It's that the strings are either installed incorrectly or the bridge plate is worn out from having the strings installed wrong too many times.