bridge and post moved after bass fell

Discussion in 'Setup & Repair [DB]' started by guillermo, Feb 20, 2005.

  1. guillermo


    Oct 1, 2004
    As I was comming back home last friday night, my Double Bass was already in it's gig bag an fell. In fact , it was lying on the right side ribs (from a guy that's playing it perspective) and it rolled , 90 dgrees, so that at it ended with the top plate facing the floor.
    It made a somehow loud ' tuck!!! ' sound that could be heard through the padded bag.
    Once I was home, I unpacked it and noticed that the bridge had moved (when I changed strings 2 months ago I had marked the position of the bridge).
    using a piece of wood and a rubber hammer I put the bridge back to it's exact original position by softly hiting
    the bridge's legs.
    After that I noticed that the soud post had moved also:
    I dont have pencil marks to prove it but there's a circular
    mark on the inside of the back plate that shows it's probable original location.

    Her goes my question:
    What should I do ? Should I leave it there ? (I noticed one thing although the post seems to have moved it looks perpendicular with respect to the top and back plates).

    The sound is OK (chaep bass with good strings anyways), playability is fine.

    Thanks a lot Guillermo
  2. Chasarms

    Chasarms Casual Observer

    May 24, 2001
    Bettendorf, IA USA
    Assuming it was fit correctly to rest in its previous location, I would return it there.

    It seems impossible that the post would slide perfectly so that it remains perpendicular to the plane of the top/back.

    If it really moved, it almost has to be slightly askew, which means that all of the top down force is pressing a small, wedge-like edge of the post. Bad.

    Read the sound post rant at Jeff Bollbach's site. You'll get the idea and likely share the concern.
  3. guillermo


    Oct 1, 2004
    Thanks for the reply...

    Since it's virtually imposible that the post moves and stays perpendicular, and I really see a straigth angle there, I'm starting to think that it did not move, and that the circular mark on the inside of the back plate is from a previous, already modified, post position.
    This cricular mark I'm talking about has the diameter of the post (of course) but it is at least ( 1/3 " = 0.8 cm) away
    from the actual post position. I do not think that the post can "jump" such a distance a land cleanly and seemingly perpendicular.

    I'll try to figure out a way to accurately measure the angle at wich the post is standing with respect to the plates
    and I'll take your advise and go get some info on how I ca re-set the post.

    Thanks again
  4. The best advice is to see your luthier - failing that, and if you have the necessary tools, it's not too difficult to re-set the post (make sure you take the tension off the strings first, though…) - you should be able to see if the marks on the inside of the top and back are the original positions of the post. Remember, the grain on the post should be at 90º to the grain on the back/top - and when the post is in the correct position (if was correctly fitted in the first place), there will be no gaps at all between the ends of the post and the back/top surfaces.

    Hope this helps -

    - Wil
  5. M_A_T_T


    Mar 4, 2004
    Regarding the inspection mirror and light tube thing pictured there, I made my own combo tool I little while ago:

    It is a telescopic inspection mirror with a 1" mirror (The only reason I got the smallest mirror is because they were on sale for $2.99) that I fed wires through, added a 2AAA battery housing to, and added a 'Super Bright' white LED to the end of. I wasn't able to fit a switch into the design at the time, so I use a piece of wood to separate the battery from the contact to turn it off. I works EXTREMELY well to brighten up the inside of an instrument, and is so compact I can get it through a 4/4 violin f-hole. Cost me about $20 to build. Just thought I'd share.
  6. nicklloyd

    nicklloyd Supporting Member/Luthier

    Jan 27, 2002
    Cincinnati, Ohio
    How far did your bridge move? If it was still up, with the string tension on, I would bet that the post didn't move. If you do not see any gaps on the top and bottom of the soundpost, (where it meets the inside arch of the belly and back), it is probably okay. Can you get it to a shop to have it looked at?
  7. guillermo


    Oct 1, 2004

    First of all, thanks for the replies, I'll inspect the inside with
    a home-made tool also. And I'll make sure there's absolutely no gaps between the post and the inside of the plates.

    The bridge moved about 4 milimetres ( 1/6 inch aprox ), it stayed up, the bass was playable but out of tune, and the G string was buzzing like crazy. It was cause of those ugly buzzes that I realized that something had changed and eventualy made a connection with the rolling of off the Bass
    (inside it's Bag).

  8. Very cool!
  9. Damon Rondeau

    Damon Rondeau Journeyman Clam Artist Supporting Member

    Nov 19, 2002
    Winnipeg, baby
    Last year I found myself in a tool store that specializes in supplying the airplane biz (a lot of that here in the 'Peg.) Those guys have some cool inspection mirrors! I was there for a threading die but left with an inspection mirror too...

    Didn't Jeff and/or Arnold post an image of an in-place soundpost around here somewhere? It was a still from a video or something like that.
  10. M_A_T_T


    Mar 4, 2004