Finding the Gap

Discussion in 'Trumpet Repair and Modification' started by dylan1, Aug 2, 2014.

  1. dylan1

    dylan1 Pianissimo User

    Oct 10, 2011
    How do you find the gap on your horn? How does the gap effect the horn?
  2. Comeback

    Comeback Forte User

    Jun 22, 2011
    Fort Wayne, IN
    Gap is the measurement from the tapered end of your mouthpiece to the beginning of your lead-pipe when your mouthpiece is correctly inserted in your mouthpiece receiver. Your mouthpiece receiver fits over the lead-pipe. According to one source (Harrelson Trumpets) the target for gap should be between .060" and .100". Some players like zero gap and some like a gap more than .100". A lot depends upon what gap seems to work best for each individual player and his/her trumpet-mouthpiece combination. Some players worry and fuss about gap and others simply make sure their gap is within reason and then forget about it and play. When I feel the need to check gap on my instruments, I use a dial caliper.
  3. trumpetup

    trumpetup Piano User

    Jan 12, 2009
    Godley, Texas
    Here is a good article on the subject. You could measure the gap without these special tools. GAP CHEK
  4. Sethoflagos

    Sethoflagos Utimate User

    Aug 7, 2013
    Lagos, Nigeria
    Couple of elastic bands, one for any old pencil shaped thing (I used an electronic cigarette) and one for the mouthpiece. With my normal piece (DW 1CW) I measured 4mm (~0.16") on both the Severinsen and Wild Thing, and 3mm (~0.12") on the Yamaha. Not going to lose any sleep over that :-)
  5. rowuk

    rowuk Moderator Staff Member

    Jun 18, 2006
    There is only one manufacturer that has quantified this issue scientifically - Robert Smith from Smith-Watkins in the U.K.

    A modern manufacturer cannot set this at the factory, except if you send YOUR mouthpiece in.

    I do not believe in GAP magic. It is in fact a fine tune parameter for many horns, and a non issue for many others. I do not believe that there is a formula valid for more than one horn. The experienced tech needs the horn, mouthpiece and player to figure it out. Everything else is senseless.

    In the case of a Schilke or Monette mouthpiece (there are certainly other brands), the end of the shank is so knife edge sharp, that we cannot speak of a GAP at all. There is only the step where the leadpipe joins the mouthpiece receiver.

    I measure gap by putting a wooden dowel in the receiver and making a pencil mark, then insert the mouthpiece and make a mark on it. Measure the difference, done.
    barliman2001 likes this.
  6. Cornyandy

    Cornyandy Fortissimo User

    Jan 9, 2010
    East Yorkshire
    Peronally I think the main gap to worry about when you play any instrument, brass or otherwise, is the one between the ears. It is too easy to play badly and say "oh my gap must be wrong" or set off on a mouthpiece safari.
  7. barliman2001

    barliman2001 Fortissimo User

    Jul 5, 2010
    Vienna, Austria, Europe
    It's not the distance between the ears, but the content in the space thus defined...
  8. rowuk

    rowuk Moderator Staff Member

    Jun 18, 2006
  9. limepickle

    limepickle Piano User

    Aug 30, 2013
    Dallas, TX
    When I take out my tuning slide and look through the mouthpiece receiver,
    I can't even tell where the mouthpiece receiver "turns into" the leadpipe.
    How could something so minuscule have a greater impact on playing characteristics
    than, say, a throat change on your mouthpiece or even a lesser change like
    a dent in your bell crook? Am I missing something?

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