Clicking valve caps

Discussion in 'Trumpet Discussion' started by trumpetsplus, Aug 13, 2011.

  1. trumpetsplus

    trumpetsplus Fortissimo User

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    Here is another blog in the series about trumpet repair and maintenance.

    That it has been inspired by my lack of adequate prepping of a trumpet I sent out for trial indicates that the egg is well and truly on my face!:sorry:

    Here is the link to the article:
    ivan?s blog

    And here is the content:

    I would like to talk about the annoying problem of valves clicking. This is a noise sometimes made when the valve springs back to its up or open position.

    It is part of the function of the valve felts to absorb the impact of the returning valve. That is why these need to be felt or another soft material. However, if they are made of a soft rubber, the valve will tend to bounce on its upstroke. This is an annoying problem which I will address another time.

    Getting back to the clicking. This is the sound of the top valve cap moving up and down on its thread. You can produce this sound on any trumpet just by loosening one of the top valve caps.

    So, all you have to do to eliminate the clicking is tighten the cap, right?

    Unfortunately, no! In situations where this noise is occurring, the cap has normally already been tightened, and tightened, almost to the extent of not being removable.

    Well, you say, the design must be flawed; the thread must be too coarse for the cap to be easily “cinched up”?

    This is unlikely; the thread size on the top valve cap of most modern trumpets is around 0.800” diameter and between 32 and 36 threads per inch (tpi). Bach, for example is 0.797” – 32 tpi; Getzen is 0.765” – 36 tpi; and Yamaha is 0.812” – 36tpi. This suggests to me that if a thread in this range is in good condition, there is no reason why it cannot be tightened down to stop the clicking.

    In other words, because it is easily possible to tighten a Bach top cap to stop it clicking, it should be possible to tighten any other similar sized cap. If we can’t do that, then there is something else wrong with the situation….

    Drum roll, please!

    A principle that should be covered in Mechanical Engineering 101 suggests:
    Difficulty in moving any sliding surface in good condition indicates excessive friction.

    When I applied a tiny amount of slide grease to an offending top cap, the clicking disappeared, and the cap could be loosened and tightened much more easily.

    Conclusion:
    Most mechanical repairs consist solely of cleaning and lubricating.
     
    coolerdave likes this.
  2. trumpetnick

    trumpetnick Fortissimo User

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    Fair enough. Very useful tip, assuming that the felts are not faulty - which happen once in a while too.
     
  3. mineo50

    mineo50 Pianissimo User

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    Jan 15, 2011
    Barstow, CA
    Thanks Ivan! I was just about ready to go out to find new felts for my MEHA. I am going to try the grease idea first.

    Jim
     
  4. amzi

    amzi Forte User

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    Northern California
    Putting a tiny dab of Vaseline on the threads of my upper and lower valve caps was something I was taught to do early in my life as a trumpet player. I later discovered that doing the same thing to aluminum valve stems helps prevent the corrosion that occurs between the aluminum stem and the brass valve.
     

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