I am sick today, so I only did a little work. I reassembled the pistons to the bugle and installed everything that affects the alignment at the MTS, so I even installed the 5th/6th levers as the bracket serves as the bell-to-1st slide brace.
In short, everything still fits; no home invader snuck in and stepped on any of these bits when I was sleeping.
Nice to know, I suppose…
Oddly, though this started as an unhappy compromise with the "wrong" valve and a cobbled-together 6th circuit, I am VERY HAPPY with everything. It all lines up better than the 5th/6th section that I was originally using.
[SECRET KNOWLEDGE: When you expand or shrink the ends of tubes to accept joining with other tubes that are not the exact, same size, you can do some very interesting things. HOWEVER — when you do this to a valve knuckle or anything VERY CLOSE TO A CURVE you run the risk of idling what I did with this tuba the first time out. Because tight curves net you metal that is far thicker on the inside face and far thinner on the outside face (as compared with an unbent section of the same tube) when you hammer a form onto or inside the end to shrink or stretch it the reshaping will be ever so slightly off center, toward the outside of the curve, as that thinner metal will give sooner than the thicker stuff. So if you want to use a very slightly larger 2nd rotor crook, you have to slightly expand the knuckles on a rotary case. AND THE EXPANSION WILL SPREAD THE TWO TUBES APART ABOUT .25 MM — PREVENTING THE SLIDE FROM BEING ALIGNED. If you expand the two knuckles ends enough to properly use the larger tubes you will make the center points of the two ports a quarter to a half of a mm wider than the centers of the crook. This drove me crazy with the 2nd slide of the Holton when I bumped the tubing up from 19 mm to 19.5 mm. The factory crook would no longer work; I had to switch to the Miraphone crook, and that required some adjustment, too.
So, you may ask, what is my point concerning this tuba…?
The two old 5th (mine, not the Swiss one) was simply a stock Miraphone valve of that specific bore. That was how I was going to run with this back then: same setup (five valves in one hand). THEN I screwed with my world by deciding to add a 6th valve because I had what I needed here at hand.
After my experience stretching the exit port of the Miraphone rotor case to fit the now-larger small side of the MTS (this tuba had some major taper issues — I corrected a lot of stuff and it plays better now) and wanting my 6th valve to have several things oriented correctly from the factory rather than it being obvious that I made this crap in my carport at home, I decided to order a custom valve from the good folks in Bavaria. My previous custom orders all had been well executed and affordable… so why not treat myself?
The second time around I ordered BOTH valves custom, so the exit ports being larger did not affect the final alignment between the piston block exit port and the small side of the MTS. So by spending the extra $$$ on the two valves, I ensured that this small "stack" was very straight from end to end. Et voila! The MTS works better than it ever has. Unintended benefits:
I love them.
And I learned a valuable lesson was learned regarding tubing expansion.
I soldered the two rotor cases together. The offset was not as much as I had feared. I was hoping for a nice, neat-looking setup whereby the two rotors were in line exactly, but this couldn't be (for several reasons, the main one being how I rerouted the 5th slide). The offset is about 10º which is fine. It does not look bad at all on the horn. The main issue was the "sight picture" of the slide tubes possibly blocking access to the bottom valve caps. The 10º offset along with an additional 10º rotation from the piston valve plane gives me a very clear path to the caps so that work can be done from the bottom (like polishing "reamer" insertion and such).
Assembled as in the photos, the MTS has an easy, even pull, tight enough to stay where I set it, but in no way binding in the pull.
I'm pleased as punch with the outcome of this work! The tuba will be a good bit better than it was before the addition of the 6th valve, and the 6th valve added some serious utility to the low end of the horn.
I think I need to give myself a pay raise…
5th at maximum pull to check clearance with the 4th valve "hoop" behind it…
Access to the bottom piston caps is excellent…
5th slide is back in; 6th is, too, but I have not yet cut the slide itself, thinking I will shorten it against the tuner, a bit at a time. I think the other legs are where I'll end up. I think this layout looks decent. I just wish the more gentle curved elbows I have had worked out, but alas, it was not to be. Boo-hoo…
Here is the dreaded offset. I do not hate it like I thought I would. The offset in the previous setup was more like 45º and made the whole thing look non-factory. This setup, on the tuba, looks like it goes there. (Yes, this is soldered.)
All this sloppy solder work is due to my vision problems: I can't see well enough to wipe it with my oiled Q-tips. What I can see I can clean. I could not see this mess, sadly. I will take care of it tomorrow before soldering the rotor section back to the pistons and bracing it all up.