Tapers - Myths and Facts

"Sorry if this has been asked and answered before.

I read on the Kanstul website that Yamaha flugelhorns use a "Large Morse taper". Presumably that means that Yamaha flugel mouthpieces are always "Large morse"?

I also read on the Kanstul website that Bach, Courtois and a few other flugels take a "Small Morse taper". In other words: A Yamaha flugel mouthpiece will not work properly in a (1960's) Courtois flugel, right?

I seem to remember that the difference between a large and small morse taper in flugel mouthpieces is a difference in shank diameter (and not in taper). Correct? Does anyone know how much?"


The industry needs standards for such things as tapers as well as terminology.

The Morse taper is not correct taper for the receiver of any flugelhorn or trumpet and this has been discussed many times but it still keeps coming up.

The correct tapers is .050” (inches) over 1” (inch). Or in Metric 1mm over 20mm as mentioned above. We must know if we are talking Metric or Inch.

Each Taper needs to be defined .050” : 1” or 1mm:20mm, these are the same! Next you need to define a beginning point. The Bach begins at .355” or 9.017mm. Finally, an engagement length must be established and with that information we can calculate that diameter. Taper .050” : 1” beginning diameter .355”, engagement 1”, ending diameter/receiver opening dimension .405”. In Metric: Taper 1mm : 20mm, beginning diameter 9.017mm, engagement 25.4mm, ending diameter/receiver opening dimension 10.287mm.

Lets take another engagement,

Taper .050” : 1” beginning diameter .355”, engagement 7/8”, ending diameter/receiver opening dimension .39875” or rounded up to .399”. In Metric: Taper 1mm : 20mm, beginning diameter 9.017mm, engagement 22.225mm, ending diameter/receiver opening dimension 10.12825mm or rounded to 10.13mm.

“In any case, Yamahas really only fit Yamahas correctly.”

This is not true, the Tapers are the same but the Yamaha requires more engagement so the shank must be able to accommodate the greater distance. http://www.grmouthpieces.com/questions.htm Flugel Tapers

Is it possible to find published specs on these different tapers or even the definition? Terminology and specs must be agreed upon by the manufactures to keep this subject from constantly confusing the trumpet world.

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