I have been using my MSO Spring Vacation to complete some of the more involved fabrication tasks. (No, not welding. But I
am fabricating, I
am a welder, and I
like the word.)
Today I realized that taking down the whole 1st slide to work get it ready for its new brace and the lever brace would waste some nice alignment work if I did not stick my proposed thumb ring bracket on first. So today I designed and fabricated the thing. It is a decent design using good materials. However, I had to do a lot of alterations to the purchased parts.
First, I want that fat boy ring that came on the horn, but today I could not work out a way to set a threaded rod in the tube (the ring is hollow) that would not end up snapping loose at an inopportune moment. I will do this, but not now.
Instead, I hacked up the very nice thumb ring from Jürgen Voigt that is used on all the Melton piston tubas. I like it, I have one on my Holton, and that was what was on this tuba until… well… today.
I had to destroy some of the parts to get the ring free. (I can buy more if I want them.)
Then I wanted to use the nice large detachable brace socket from Instrument Innovations, and to fit that Voigt ring I had to hack up two of the three socket parts so I could get the stupid torch flame onto the join line between the socket "plug" and the end of the ring's post.
In my haste to get the joint silver soldered, cleaned up, and buffed — SOMEHOW — one of the two parts in my jog shifted just a bit, so the ring is on the plug a bit crooked. Whatever. I was pissed off but got over it quickly because all of this is readily available and affordable. The only messed-up parts are the plug and the threaded barrel. The ring is fine; I can saw off the plug and start over if I decide to use this ring long term, and if not, I can still get the two parts for the other fatty ring, saw off the boo-boo on this ring, and use it for something else. No real loss except for about ten bucks in parts. The education was worth many times that, TBH…
The arm itself was cut from that bar of quarter-inch-thick nickel silver, and it was a bear to cut that long curve with a Dremel, but I did it, and it came out very close to the profile of the radius of the 1st valve knuckle to which it will be soldered. (It was a PITA because the "radius" is really a freeform curve and not a segment of a circle. I managed to find *one* slide crook of the correct bore size to slip over this knuckle nicely and that had the same odd curve line. Once that nickel silver arm had been cut and fit to the knuckle I then located where I needed the base for the thumb ring to be and traced my outline of the outer edge of the part. Then I cut that out and finished all the edges with a Dremel sanding barrel and a tone hole file.
I fit the flange (from the Olds slide crook I had hacked up) to the knuckle very carefully and then went outside to shape the thing, taking down all the shape corners and shortening each end just a bit from what I had initially wanted. (This will give me more wiggle room when soft soldering it to the knuckle between the 1st slide tube (that could go a little bit out of alignment with all the heat needed to flow solder under this very thick chunk of metal) and the piston casing, which will act as a heat sink (so distance there helps keep the part hot rather than wasting heat on the casings).
The finished product fits very well and looks pretty nice. It has some nicks from the Dremel because I am old and blind, heh, heh. The threaded boss for the ring is just surface mounted, but the silver solder bead is very nice and got 100% contact. (It is hollow, so I could see the silver solder line inside and out, and it was perfect, thank you very much.)
I am just pissed at my missing that the ring base and the plug had somehow shifted before I stuck the together. Again, it is a nuisance but pretty easily fixed now that I know exactly what needs to be done to these parts to make them work for me.
My only real fear is that the brass flange is now annealed. If it is too weak to keep the thumb ring bracket's torque at bay the arm could bend. If the flange fails in this manner the knuckle beneath it could be crushed or torn. But this is close to how Herr Kurath does it on his Willson tubas, so maybe it will be fine.
Time for the horn porn…
This took a stupid-long time to cut out.
After I altered the chunk of slide crook that became this flange, the part was now too long. I was not sure whether I wanted to just lop it off even with the flange or not, so it stayed in place for several more steps.
Ready for me to check the fit against the knuckle using my "eyecrometer"…
The fit is excellent with no gaps underneath to weaken the soldered joint. And yes, the tongue can get lopped off flush.
Tongue lopped, boss mounted, ring "Frankened" — and it all looks pretty good despite the crookedness of the ring. I am lazy, so it may stay that way if it is strong enough. We shall see…
To distract you from the wonky ring post, note that this sucker got away from me when I was buffing it. (First time for that fun experience in a long time.) Two corners of the flange were bent up, but I only fixed the upper one because I did not notice the lower one until just now when I saw this photo. Dang it! I'll tap that out before I solder it to the knuckle. Also, the thumb barrel got melted in two spots because of the difficulty in getting that joint between the plug and the ring base. Of the four parts, the ring and the threaded boss on the plate are perfect. The barrel and the plug need to be replaced, and I will do that *someday* because it bugs the crap out of me.
Yep, that corner is bent and I cannot believe I did not see that. Well, yes I do. I was in a hurry and overlooked it. D'OH! Overall, though, this came out just about the way I wanted. It places the ring about a half-inch closer to the valves for a perfect fit for my hand span, but to make it longer would be to make it more able to flex, endangering that valve knuckle. This was a compromise, but I think it was a good idea. Anyway, it will allow my hand to rotate to the correct position so I am not playing 4th with the 2nd and 3rd joints of my pinky. It is also an inch lower than it had been, and I did not lose any of that. MUCH BETTER!
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