my new soundpost measuring tool

Discussion in 'Setup & Repair [DB]' started by jonas, Jan 11, 2014.

  1. jonas


    Dec 9, 2003
    Frankfurt am Main/Germany
    Kontrabass-Atelier, Lando Music (Germany)
    I had some time during the Christmas holidays, so I’ve built my own measuring tool which will hopefully save me some time in future. See photos at
    The shaft is a aluminum tube of 10 mm diameter. On one end, I glued on a steel ball with epoxy. On the other side, I inserted a brass thread and a screw (M8) for length adjustment, again with a steel ball glued on.
    Then, I put magnet rings on both steel balls. The power of magnetism holds them firmly on the balls, but will allow the to follow the curvature and angle of back and top smoothly – that’s the key idea of this device. With some sandpaper, I’ve dulled the balls’ surface, in order to prevent the magnets from moving too easily. I now set the device to the guessed length of the upcoming soundpost, set it into position inside the bass and re-adjust the length if needed. The magnets are much slippier than soundpost wood is, so I glued on fine sandpaper. Once the device has the proper length at the correct position, I remove the device carefully (so that the magnets stay in their position). For inserting and extracting the device, I use a fixed bent wire instead of the S-shaped soundpost setter tool – but this still needs some improvement. Besides this, it’s pretty cool. Transfering the angles to the soundpost is still a little tricky, but much better than guesswork.
  2. 360guy


    Apr 28, 2006
    Lansing, MI USA
    That's clever. I usually check the fit with a boroscope. The advantage of the scope over a mirror is that you can see on a cross-plain to double check the proper fit.

    And I use the same tool for close up inspection inside the bass in other areas as well. Now that I have it I wonder how I did without it!
  3. notabene


    Sep 20, 2010
    SF Bay area
  4. Jake deVilliers

    Jake deVilliers Commercial User

    May 24, 2006
    Crescent Beach, BC
    Owner of The Bass Spa, String Repairman at Long & McQuade Vancouver
    Nice work, Jonas! ;)