Thanks, Dave. 14-K it is!

Hmm, I had the same question -- my old brass Conn sousy dates from '59/'60 and has "Made in Elkhart" stamped on the 24 inch bell. It has three regular pistons. BBb. Anyone know what model it might be?

Right? That screw kind of pulls the whole tuba together.

I'm selling a gorgeous old pre-WWII Czech-made helicon that I bought off German eBay like ten years back. Here's the highlights: It plays... eh, not great, but it plays. It's leaky, as you'd expect of an old (~90-100 years) rotary horn, though heavy oil helps with this, but it can be tricky to land ...