Tim,
I cut a tenon on the horn and fit the mouthpiece over it. I got just a bit too ambitious and filed the tenon one stroke too many all the way around, so it came out just a little bit loose. Some epoxy slury took up the space. I did not pin it.
thanks, good to be here.
Kermit,
Tuba, Sousaphone - sound wise pretty much one and the same, to my ear anyway. If you ever get a chance to hear a Dixieland group called the Missouri RiverBoat Men play, the Sousaphone player is a guy named Red. No body ever told him he was not playing a trumpet. it's a thing of wonder to hear him play Flight of the Bumblebee on it. Pure amazing.
John