The Great Kurath Re-Tubing

[the elephant]

I figure on keeping the collection on my bench in an old Smuckers bottle.

I'll call it my tip jar.

Thank you! I'll be here all week. CDs and teeshirts are available in the lobby.

[hrender]

[Three Valves]

I figure on keeping the collection on my bench in an old Smuckers bottle.

I was on my scrapple page and someone was talking about Stoltzfus scrapple. I said “with a name like Stoltzfus, it has to be good” (Lancaster county PA/Amish joke)

He says, “haha, I married a Schmuckers”

[the elephant]

Okay, I am moving along, here, at my normal glacial pace. I just purchased several 5/32" x 12" nickel silver rods that I need to make the linkage arms to connect the 5th and 6th valves to the levers.

Progress!

No, really: I need this stuff. Okay, I'll admit that this was a pretty small incremental step in the process.

Sorry.

I have the 6th linkage arm mocked up using coathanger wire high-tech modeling rod. It will be complicated to thread and bend and will require some homemade parts to keep it aligned while moving, but it ought to work pretty well. The route is convoluted, but clear, and the spring rate on the lever is very tuba-like despite being old horn parts.

The 5th rod will just be a straight rod with the same threaded ends. I plan on using my semi-functional lathe to turn down the OD and then thread the ends. This should prove to be an event filled with delightful epicaricacy* for everyone. I will try to make a video of the process.



_______________________

* Getting to use the word "epicaricacy" in a sentence was the actual reason for this post, heh, heh, heh…

[bloke]

epicaricacy = You're just trying to make me feel even more inferior for (simply) using 3mm stainless steel rod (with threaded ends) to push links...

...and for not owning any Swiss-made instruments.

bloke "drooling over that Jinbao ophicleide on eBay... not"

<sidebar>
The 1964 5-valve 186 - that I'm trying to super-sonically nice-up and push out the door - I FINALLY got horrible/very-stubborn rattle-can lacquer (which someone had sprayed over the o.e.m. lacquer...wtf...??) to strip, tonight. I'm quite happy about that. Previously, that tuba looked like a house - with badly worn paint - covered in sleet...awful...
</sidebar>

[Rick Denney]

…

...and for not owning any Swiss-made instruments.

…

Did someone say Swiss-made instruments?

In today’s UPS truck:






Rick “who doesn’t need a 12” thousandth-reading precision vernier caliper with micro-adjust?” Denney

[bloke]

<out in left field, again>
I had a Chinese digital 12", but - electronically - it bit the dust.
It sometimes seems (??) to want to work.
If there's anyone who knows how to tinker around with tiny electronics, I'd be glad to swap a mouthpiece rim or shank for having that thing working again.
</out in left field, again>

[Rick Denney]

That’s why I bought a vernier. No freaking batteries or electronics, and more robust than a dial (though I also have a Tesa dial caliper in a smaller size). I checked this one against my mics, and it’s accurate enough to read to .0005, with vernier interpolation. It’s stiff to operate, though.

These sell for pennies because nobody knows how to read them.

Rick “been reading vernier scales on surveying equipment for 45 years” Denney

[bloke]

I keep a dial calipers, for when my batteries die, and I don't want to go into the pantry in the house to get a battery.

[the elephant]

These sell for pennies because nobody knows how to read them.

I own a nice, old Starrett dial caliper but cheat and use the cheapo HF Chinese digital one because I am always dropping stuff. I want the dial caliper to stay accurate, so I don't use it much. The cheap ones are "good enough" as Joe likes to say.

I know how to read and use the Vernier scale, but it hurts my wee brain. My Mitutoyo micrometer can also do this to me if I have not had enough coffee in the morning.

<think, think, think> *snap* "OUCH! I broke my Stupid Bone again!"

[the elephant]

I started the process of designing my way out of the corner into which I have painted myself. It looks like it will work, too, and not look terribly Rube Goldgerg-ish when it is completed. (Well, maybe not…)

Here are the beginnings of the mount for the lever rack. I had to move one screw location inwards so that it now lives beneath the 5th lever. This gave me clearance for the barrel connector of the detachable brace to the bell to fully unscrew and slide to the rear so the two halves can separate correctly. Of course, the stub end of the rack where the original screw hole was became this appendix sticking out into space with a hole that would never see a screw. Giggity. So I cut that off.

The two mounting bosses will have the brace post silver soldered to them and to the bracket. I want the torsion from using the valves to not skew the 1st slide action, so I silver soldered part of a tube to it to help distribute that torque around the outer slide tube a little better. I have a feeling that the 1st slide action is going to suck now, no matter what I do, but there really is no other location for these levers that are usable. Anyway, the back half of that tube will be cut off and the edge finished, and the whole assembly will be soft soldered to the 1st slide.

Here are some pics. I have some cleaning up to do to my sliver soldering bead to the ferrule and some other messing around to get things to fit. Then I can braze that brace rod to the whole thing. This will completely replace the existing detachable brace between the dogleg and the 1st slide, and the lever rack will screw down to it.

I hope.

Aaaaand pics…

The flattened section will be cut out soon, so it is not of concern…


That is not a gap in the silver solder. It is buffing dirt. I promise.


Off-center holes courtesy of some nice German worker a half-century ago…


Whoops! I left a bit of Tripoli compound there. Sorry…


I need to make a larger, longer pull ring for the 2nd slide, so I might hack these up for that project.


My difficulty holding the horn with this new valve setup may be fixable via an adjustable thumb ring and a pinky hook. These might be sacrificed to the cause.

[bloke]

ahh Bachhh

[the elephant]

Captain's Log: Supplemental.



This is how the paddle rack looked last week. You can see how both "ears" are still there, with their screw holes. I had to lop the one on the right off and move the screw location to beneath that lever. By doing this the rod that will be attached under the rack can extend the correct distance both to reach the brace socket (bottom, right) to the right side and to allow that fat, knurled thumb barrel to be fully unscrewed and to slide over far enough to "uncage" the brace halves from one another. I now have the room needed for that tumb barrel to move fully in both directions. THAT is why I hacked up everything today.

[the elephant]

Okay, so now I have a replacement for the deleted 1st slide brace that doubles as my lever rack mounting point.

I'm not fully convinced that this thing won't break.

For *me* it is far easier to scratch build stuff to fit an existing space than it is to scratch build everything with no reference points. So, once I have had this horn up and running for some time, I can see if anything might crack or break. I can then look at each part of the system and make needed adjustments.

So far I am pleased and cautiously optimistic.

I hope I got it right; it's always fun when you design and build something right the first time.

I still have to take down the 1st slide, remove the thumb ring base, clean up all the solder mess, rebuild it with a new brace, and then install this gizmo.

This is what I made yesterday. I have to silver solder the brace rod and the other mounting boss as well as the detachable brace parts to this to make my funky brace.




Okay, the silver soldering is complete. Now for the pickle bath and then some buffing…


Here it is! Woot!

[the elephant]

beautiful!

[Tubajug]

Looks great! What do you use to buff those little nooks and crannies?

[the elephant]

https://www.baldor.com/catalog/111

[prairieboy1]

Wow! That's a beautiful piece of work!

[the elephant]

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!

[bloke]

I’m probably missing a detail, but can you put the ring in your vice - between a couple of pieces of corrugated cardboard - and whack the post a good’un with a hard plastic mallet ?

bloke “I’m sure that manufacturers NEVER lose anything on their buffing machines, and NEVER straighten them back out - prior to installing them on new instruments. “