What is known about this mouthpiece? Specifically the small shank version of it. Is it the same rim as the bass trombone version? What model(s) did it come with? Did he also use this mouthpiece or did it just have his name on it?

The 14H uses a small shank mouthpiece (this is the F-attachment horn from the 1920s, not the Director). I would suspect that it is small compared to current bass trombone mouthpieces. All mouthpieces of the period were much smaller than we play today. I have a tuba mouthpiece from my 1892 Conn Eb tuba that is smaller than a Schilke 59.

[quote="BGuttman"]The 14H uses a small shank mouthpiece (this is the F-attachment horn from the 1920s, not the Director).[/quote]
Not entirely true. I had one that was a large shank .547” single bore.

The reason I ask is because I picked up a really trashed one. I like it because the small shank is extra small and fits some Olds horns I really enjoy playing. It plays fine. A little more difficult to do some things, but I think that’s part of not being used to it. It’s much much different than what I play normally, of course. Comfortable enough rim. I played it for a bit against my regular DE setup before I had to go out and didn’t notice anything special/different/weird about it being so old of a design.

I’m not on a hunt for a nicer one or for the other versions, but I’m always curious about old mouthpieces. I love the outer shapes and the weight of these old Conns the most. I need to stop cluttering my shelf, though