Broken valve top screw thread...

Discussion in 'The Rehearsal Room' started by B.Portas, Dec 12, 2013.

  1. B.Portas

    B.Portas Member

    Right, so straight onto the issue here.

    My tuba is a 1920s Boosey & Co Imperial - I love it to bits, but it has a recurring problem that has only started a few months ago. Basically, any time I use the 3rd valve, the valve top (not the finger button…hopefully you know what I mean) unscrews itself, then the valve pops up from the case and whatever I was playing turns to ****. It seems that the screw thread has worn down (on the valve case or the actual top itself, I haven't checked).

    I've tried screwing it on really tightly, but still, that only holds for a few presses of the 3rd valve, before it's rattling again, and ruining anything I play.

    I'm taking it for an overhaul in the new year, but I still have plenty of Christmas concerts to go, and not a lot of cash right now.

    Is there anything anyone can suggest to alleviate the problem…aside from alternate fingerings!


  2. Adamskied

    Adamskied Member

  3. B.Portas

    B.Portas Member

    Even if that was a joke, I'm considering it as a short term option…
  4. P_S_Price

    P_S_Price Member

    Cotton in the thread as you screw it up
  5. Ianroberts

    Ianroberts Well-Known Member

    Plumbers P T F E tape
  6. Adamskied

    Adamskied Member

    Good one Ian...could not think of the name of it lol

    Should be good
  7. The Wherryman

    The Wherryman Active Member

    You could try Loctite, which is designed to 'seize' a threaded joint, but to still be removable at a later date.
  8. iancwilx

    iancwilx Well-Known Member

    A bit of polythene wrapped around the thread will do a temporary job. Ians PTFE tip is a good one to try as well. (Wrapped clockwise of course)

    When you do scrape up enough dosh to have it fixed I'd be interested to know how they do it.

    I don't think it will cost you an arm and a leg.

    ~ Mr Wilx
  9. Aussie Tuba

    Aussie Tuba Member

    I had the same problem with a 1923 Boosey and Co Imperial Solbron Euphonium . They fixed it but I have no idea how. It plays great now.
  10. phildriscoll

    phildriscoll Moderator Staff Member

    I think that the technique is to flare out the thread area of the valve a bit and then recut the thread. Owen Wedgwood, the Brass Doctor, is local and very good at this kind of thing.
  11. Neillyboy

    Neillyboy Member

    Phil that is exactly right. Not a big job but it's a tad tricky!
  12. Cornet Nev.

    Cornet Nev. Member

    The flare out method does work well, ideally done into a threaded steel ring screwed over the threads first to prevent over expansion, and possible splitting of the brass.
    However as a temporary fix the PTFE plumbers tape as mentioned earlier is the best answer as this will not damage existing threads, unlike adhesives, which might when eventually forced to unscrew it.
  13. B.Portas

    B.Portas Member

    Update, it's definitely the valve top, not the case, so that's a good sign - I tried it on the other valves and the same thing happened. Its back on my third valve, as I use that least - and the thread of cotton in the screw thread worked a treat to get me through the Christmas jobs - only 2 more to go now, and it should hold up well.

    Thanks for the help :)

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