Neck Heel repair failure, Help!!

Discussion in 'Setup & Repair [DB]' started by dmeador11, Nov 25, 2013.


  1. dmeador11

    dmeador11

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    I have an American Standard Upright Bass that had a bad neck repair when I bought it. Finally decided it was time to fix it and strip off the yellow and black paint job while we were at it.
    The neck had a large Lag Bolt drilled in through the fingerboard.
    The heel crack was anything but a clean break.
    The luthier pulled out the lag bolt and used a dowel rod. after getting the thing put all back together the heel repair failed under the tension. He said he just heard it pop from across the room.
    Pulled it apart, fixed it again and it failed again under pressure.

    IS there another option or should I start looking for a new neck??
    Who makes such a neck that would fit this bass??
    Thanks for your help.[​IMG][/IMG]

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  2. KUNGfuSHERIFF

    KUNGfuSHERIFF

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    The neck is scary, but it may only be half the problem.

    One of the problems Kays have is that the neck block fit is really loose. This made them easy to assemble, but having air space under the neck tenon is a really bad thing. Without support under the full length of the tenon, there is space for the tenon to collapse into.

    If I were you I'd have the heel repaired well, with hide glue if possible or urethane glue if hide glue won't hold, reinforce it with a new bolt countersunk through the butt end of the neck heel (which is a controversial repair) and have everything shimmed up nice and tight before the neck is reset.
     
  3. Jake deVilliers

    Jake deVilliers Supporting Member

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    GRASSHOPPER:
    - its not a Kay, its an American Standard
    - urethane glue is an abomination before God
    - a French dovetail needs space at the front but that doesn't mean that the fit on the double tapered mating surfaces is "loose"; quite the contrary.



    OP, you need an experienced DB repairman to fix that heel. It needs to be thoroughly cleaned, blind dowelled and glued with epoxy. It doesn't sound like your luthier has much experience with breaks. :(
     
  4. dmeador11

    dmeador11

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    The luthier has repaired quite a few breaks but mostly on Kays but admits he has never had one give him this much trouble. Her has played bass in a Bluegrass band for 7 years here in Florida but is the only Luthier I have found within 50 miles.
    He did put a dowel rod in it and fixed up the dovetail joint. I was there and helped him put it back together the second time. That being said there was some gap space under the dovetail joint. I haven't seen it since it came loose again or I would get you a picture.
    What type of epoxy do you recommend??
    How do you feel about the countersunk bolt idea?
    Thanks
     
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  6. KUNGfuSHERIFF

    KUNGfuSHERIFF

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    Jake, do you remember the '39 King I had? The neck pocket was sloppy as hell. What I said about filling voids was recycled from Arnold, and it worked when I followed his advice.

    The urethane glue thing sounded weird to me too, but when I was in the same situation as the OP earlier this year, a luthier friend fessed up that that was his method. He's been at it for 37 years...
     
  7. Jake deVilliers

    Jake deVilliers Supporting Member

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    I think I remember the King...

    The joint on that particular bass may have been sloppy but it wasn't because a French Dovetail is "inherently sloppy". The joint may have been loose for 25 years and the neck banging around in the block made some extra 'room'. The block may not have been dry enough at build time and shrinkage over the following 50 years would have made extra space in the joint.

    Plenty of old simple mortise & tenon neck joints need to have maple shims added when the neck is reset, too! ;)

    I use real 24 hour epoxy for permanent bonds because it is used for that purpose in the maritime and aircraft fields. Urethane glue, not so much. I've been using epoxy for 35 years and trust it.

    To be clear, I use wood and epoxy for the heel/neck repair, often with a short 3/8" or 1/2" Maple blind dowel to counter the shear loading, and re-glue the neck into the block with hot hide glue after re-fitting and shimming as necessary.

    I repair a lot of broken school basses and haven't had one fail yet.
     
  8. james condino

    james condino Spruce dork Supporting Member

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    There are two things in my shop that I flat out refuse to work on and will get you turned around and pushed out the door:

    -Any bass with old epoxy repairs

    -ALL Chinese instruments

    j.
    www.kaybassrepair.com
    www.condino.com
     
  9. dmeador11

    dmeador11

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    I'm gonna go with the epoxy and blind dowel method. Hot Hide glue for the reset.
    If we shim up the dovetail joint, What about the airspace between the dovetail and the block?
    How do you feel about 1 bolt or screw to give support if we take off the fingerboard??
     
  10. dmeador11

    dmeador11

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    Or maybe not.
    James Condino, I'll let you borrow the '55 Chevy if you give me the solution to this problem. Actually the Bellair belongs to my friend Jack but who knows.
     
  11. KUNGfuSHERIFF

    KUNGfuSHERIFF

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    Jake,

    The block on that King was cracked but the mortise was cut straight. The tenon was cut poorly, with much more wood on one side than on the other. I was surprised it was that off considering the H.N. White reputation for quality.

    I certainly didn't mean to imply that ALL French neck joints are inherently bad. If I gave anyone that impression, I apologize for my sloppy language.
     
  12. james condino

    james condino Spruce dork Supporting Member

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    Warm it up for me; you've got a pm!
     
  13. Jake deVilliers

    Jake deVilliers Supporting Member

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    I'm pretty much dead set against using any metal in there - I just don't think its needed or helpful.

    Dry maple or birch dowel in 3/8" or 1/2" diameter will have a similar expansion rate to the existing maple neck and not add extra problems...

    I've never filled the front of the joint, either on bass or guitar - I'd hate to be the next guy who had to take the neck off...I think it would be better to convert it to a simple mortise and tenon.
     
  14. dmeador11

    dmeador11

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    Thanks for all the advice, I appreciate it. I will let you all know how it turns out.
     
  15. dmeador11

    dmeador11

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    If I was going to use a bolt through the back of the heel, What size and type would you use? The Bass is back together and strung up and it looks great, however when you tune it up the tension is pulling down the clearance on the finger board. I am afraid that the repair joint is still a little weak. I would hate for it to pop again.
     
  16. james condino

    james condino Spruce dork Supporting Member

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    Only if you use a dowel that is cut with the same grain orientation and direction as the neck. If you use it in the common method that is 90 degrees off from the neck, you will actually create a zone of more opposition and movement that will cause more issues and problems with an already weak repaired neck.

    If you are going to use a dowel, from the standpoint of movement, a tapered dowel in a tapered hole that has has been turned on the lathe with the correct grain orientation is your best bet.

    It sounds like the neck joint was not a very good fit when you put it all back together. If you did the work with hot hide glue, you can easily steam open the joint and add a few shims to tighten it up and then reglue everything. If you opted for the epoxy...well.... you are about to learn a valuable lesson on why some of us don't like to work behind epoxy.

    Do the best with what you have and try to make a decision with a method and a specific outcome in mind. Some of us are concerned with the type of glue, others the use of internal hardware, and others maintaining a pure wood connection. Some think that they will own the instrument forever and nobody else will have to work on it; others are convinced and terrified that you'l bring t to their shop to fix the fixes. You've gotten plenty of information, now just pick a method that feels right for you and get to it. Remember that in the long run, they'll all eventually wind up in the landfill or some cowboy's fire....

    Does this mean I can't have the Chevy this weekend????

    j.
    www.kaybassrepair.com
    www.condino.com
     
  17. dmeador11

    dmeador11

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    We put the dowel in with the epoxy and used hide glue to reset the neck. We shimmed it up pretty snug to the point that it was real tight sliding it back in. Every time you take the dovetail joint apart you lose a little more wood. The heel on the American Standard bass is so small in comparison to even a kay.
    The repair is holding but it loses some of the clearances when tuned all the way up. I was considering putting a bolt in from the heel to under the fingerboard to add more strength.

    What are my options for a replacement neck for this base, with the long string length???

    AS for the chevy, she is getting new shocks and struts this weekend.
    Thanks
     
  18. misterbadger

    misterbadger

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    Isn't a dowel cut in the same direction/grain orientation as the neck heel going to be cross-grain and weak? Also, wouldn't a tapered dowel in a tapered hole result in zero clearance and a glue-starved joint, particularly if epoxied? Maybe I'm misunderstanding...
     
  19. bassfacedesign

    bassfacedesign Supporting Member

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    Put the bolt back or get a new neck.
     
  20. bassfacedesign

    bassfacedesign Supporting Member

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  21. tyb507

    tyb507

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    Well that settles it!
     

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