The rotor block and linkage has been giving me a lot of trouble. I had to use corrosion cracker three times under heat twice and about 5 days to free up the screws that held the linkage on the valve block. Once this was free, I unsoldered the braces, removed the tubing, and ultrasonically cleaned the valves and casings. No need for the tubing anymore!
Trying to figure out a way not to machine a whole bunch of new parts or trying to find parts to work, I looked at the linkage braces - these would work if I mounted them back on the valve block. I tried this, but soon discovered that, although the linkage hooked up with the stop arm on the rotor, it wouldn't fully depress. So now I either have to file off a millimeter or two from the braces or add a washer to each side to bring the linkage up. It should work since the distance between the "S" links and the stop arms doesn't change, just the height.
I had wanted to know where the valves needed to be and some length of the overall bugle, so I grabbed a F horn off the wall and started sizing things up to get the correct valve/left-hand placement. After that I started planning how I would add the extra tubing needed to drop the pitch to BBb. Unfortunately, this quick measurement gave me about 222" or 18.5 feet! And this was without a tuning slide! Now I'm going to have to readjust the open wrap in order to place a main tuning slide and still looks like a french horn.
Still need to find a leadpipe - it was recommended that I locate an Allied universal euphonium leadpipe, but I might have to have a custom leadpipe made to expand to the .687" bore needed for the main slide and the valve block. Also a mouthpiece that resembles a french horn mouthpiece but fits the bass trombone/tenor tuba shank receiver. Lastly a whole bunch of tubing to bend into shapes and most importantly ---- a collar and tenon for a removable bell!
Worked on the bell today. Took a scrapped euphonium bell, cut the rim off and part of the throat to the approximate sizes needed.
Unfortunately the rate of expansion of the euphonium bell is slight more that the taper on the sousaphone bell. I'm going to try and see if I can mount a male/female collar/tenon for a removable bell right where those parts are so that the difference in the tapers won't be as obvious.
I like bass versions of instruments, hence why I built a bass trumpet.... Way back in grade school, I started on French Horn and played it for a few years until the middle of 8th grade, when I switched over to tuba. Sometime ago, I ran across Roger Bobo's Bass Horn in CC and then saw Tim Sullivan's CC version using a sousaphone body.
Both of these are interesting instruments - Roger's is close to a french horn in terms of it's design, while Tim's is like the second or third movie of Honey, I Shrunk the Kids! (Honey, I Blew Up the Kids!) and is a mammoth/jumbo french horn.
The one thing I don't like about Roger's is that there are several loops after the valve section, where as on a French Horn, there's only one loops and then the bell.
On Tim's I'm not a fan of the short leadpipe - it works for him and that's what matters most.
For me though, I thought about using a Buescher Eb helicon, but this was just a bit too big and would require another wrap of tubing like Roger's bass horn.
So I came across an ad for a mini sousaphone - one of those Barcone Italian-made mini sousaphones that have a tiny bore and are very much a 'joke' instrument. This was about the perfect size for the body and the bell was about the right size, so I bought it. It showed up and was better than I hoped, well for the most part.
Naturally, a French Horn has to have rotary valves, I took a tenor tuba or the world's largest euphonium and removed the valve section. It's a four valve rotary block with about a ~.684" bore, I should be able to make the King standard parts work instead of trying to find more of this tubing or drawing the tubing to several sizes. The best part is that the valve section nearly fits right where the valves would be on a French Horn! I still need to remove all the tubing and flip the block over and figure out how to make the linkage work...
Anyway, The body was dismantled and the original valve section removed, then buffed and set aside while I worked on the bell. Removing the collar and the bell tenon, leaves just the bell flare. I need to find either a baritone bell to use for the throat or make a new section to fit between the bell flare and the body joint. I've measured the placement and I need about 7 inches between the body and the bell, but an 8 inch section of a bell to fit the body... I may have a baritone bell to use for this. Then I will have to cut the middle and splice in the removable collar and tenon, so that the bell can fit into a more convenient case.
The bell is 19-inches and the body is about 21 or 22 inches wide. Hand-stopping should still work fine on this.