Dating bach trumpet mouthpieces
it simply has "FRANK HOLTON & CO" "HEIM MODEL" with an inner diameter of .620 or so with a deep V shape and a flat rim, very small in height and weight.
I think it's from the 30s and seems to follow the description of the #1.
I measure here 3 diferent 10 1/2 C at .645 and one at .633 Most modern 7c are about .650 The heim 1 is a lot deeper than a heim 2 but should be about the same diameter.
They vary._________________Mouthpiece Maker vintage Trumpet design enthusiast of my posts are done with my phone on the fly, and it will sometimes auto-correct in some pretty unusual ways.
The C signifies it has a Chambers cup (as in James Chambers, longtime Principal Horn of the New York Philharmonic) with a number 2 bore.
The gustat 2 looks like it originally the same as the gustat 1, and then altered to make the diameter .010 bigger, and with more of a higher alpha angle.
That's just from looking and and seeing comparing the molds of the two pieces I have.
However, over the years the production standards changed as the company itself changed hands.
On the left in the photo is the oldest Giardinelli horn mouthpiece I own.
One of the classic, old standard brands of mouthpieces in the United States has been the series produced by Giardinelli.