The Great Kurath Re-Tubing

[Three Valves]

We actually had a tornado warning in Chevy Chase MD recently.

Wife made me go in the basement…

This ain’t tornado ally…

[the elephant]

Because of a boneheaded move on my part, I am hugely disappointed today. Perhaps one day I will get to do what I had wanted, but for now, the old crap has to go back on the horn.

I should not have "saved time" by doing a step out of order. That is all I will say for now. After I have a better time in the shop (this afternoon? tomorrow?) I will elaborate. I am eating lunch and fuming, so now is not a good time…

[the elephant]

Okay, so I silver soldered all my homemade flanges to the new brace threaded bosses, and I was very pleased with my work.

I carefully shaped the flanges to fit the radius to which each would have to conform.

Nice!

Except that today I learned that I curved them all for the WRONG END of each brace. These bosses come with a radiused bottom end that fits perfectly onto a trombone-sized tube. Silver soldering these takes more wire to fill the gaps, and baby, I did a great job for each of the eight bosses, each one being slightly angled if needed… a genuine custom job.

So now, to bend all the flanges to fit there are two sharp protrusions inside the flange from the two sharp ends of the radiused surface. All eight are ruined.

I can try to un-braze the flanges to save the threaded bosses, but this does not always work. Plus, they are NICE! So I think I have to buy eight more of the bosses, which are not cheap (close to $50 for eight of them), and cut out eight more flanges from my limited nickel silver sheet stock. The stuff I have left is very thin, too. I may have some solutions for all this, though.

So this means that — for now — I will have to reuse the King 2341 braces I installed years ago, but everything needs to be a little bit longer to fit the new gap. It is not the end of the world. It was just a genuine pisser to make this discovery.

Also, I was convinced that I had bent one of the knuckles (4th-to-rotor or 1st-to-leadpipe) or that I had tweaked my leadpipe. If this had happened then the adjacent piston might no longer work well, and I do not have a slug/sleeve set for this valve set (a future purchase, since two of my three horns, use the same valveset) and I do not have a set of adjustable reamers with the edges polished off by a machine shop. I have one reamer, it is too large, and the ten blades all retain their cutting edge, so no way, José.

After a quickie cleanout of the casings with denatured alcohol I oiled and installed the four pistons… and all work just fine.



Then I did some checking into slide-to-slide alignment and the leg-to-leg alignment of the upper 3rd slide. In photos and from certain angles (in person) things look really wonky. After a careful inspection that included a lot of measuring I am accepting everything except for one slide (rear 4th) that I had already promised to fix once the detachable brace system was installed.

I am actually pretty happy, overall. Except for the very nicely done brace parts I ended up wasting. I will use them, but not for this project. So once I have disposable income again I will order another set of the bosses and (if I can get them) eight ready-cut flanges. Or I will spend a morning marking and cutting and dressing eight from sheet stock.

I need a disk puncher that can cut this gauge of brass… hmm…

[the elephant]

Enough navel-gazing! BACK TO THE SALT MINES!

Today I will be knocking out all seven detachable braces. I hope to have progress to report tonight.

Until then: Adios, y'all!

[prairieboy1]

[the elephant]

Today was "Get Sh¡t Done Day" and I, indeed, got 'er done. Well, I got some stuff done.

Whatever…

I spent a lot of time yesterday and today checking slide circuit alignment across the machine, making sure I did not FUBAR my valves, and adjusting the lengths of the detachable braces. I (shudder) reused the King braces, which are inferior in every way, especially in strength. I will buy the needed parts in the future and do what I wanted to do in the first place… someday.

I ditched the Yamaha sousaphone brace and replaced it with another King brace. I am much happier with this. There are four of the King braces and two of the twist barrel braces. One detachable brace location was ditched. I installed a fixed brace in a better location, and this change uncomplicates the reassembly process while providing about the same resistance to bending.

I also recycled the crappy 2nd pull ring by putting it on the 6th slide crook. I hate the thing and will replace it with the same type that I used on my Holton. It's made by Jürgen Voigt. That is an easy change to make, and this one works; it is just very thin, it is not round, I have re-rounded it twice in ten years. I dislike it because it is WEAK, THIN, and SMALL. Once I get it the Voigt one will make me smile. Until then this crappy one will do just fine.

The wonkily installed rear-side 4th slide got lined up much better on the machine today, too, and that also makes me pretty happy.

Tomorrow I will do some last brace work and start the cleanup process. The original 5th linkage and my thumb lever will be installed for my three upcoming F tuba gigs, and then I will work out and make the new linkages.

Here are some pics from today…

This was taken to check whether I hung the machine on the bugle straight. This looks pretty decent, and everything works correctly, so I'll take it.


Hike up that skirt and show a little leg, honey…


A wonky slide…


A non-wonky slide…


A non-wonky slide from another angle… (Again, these were taken so I could look at this away from the actual horn to confirm what I was seeing.)


Braced up using the King braces that I would like to one day replace…


King brace up close…


A forest of braces…


6th and 2ndL: big slide, little ring; little slide, big ring. How poetic…

[the elephant]

Obligatory crappy video…

(Focus. FOCUS!)

[the elephant]

[the elephant]

Looking good!

[prairieboy1]

Looks great! Have fun playing your Kurath!

[the elephant]

The 6th lever is a real doozie, but it will work great once I have all the angles correctly dialed in. However, this rod is junk. I ruined it.

Once I bent a nice copy of the wire mockup link arm I realized that it actually was not the right shape. It took me several re-bendings to realize that 1.) I was not going to get it right using that method, and 2.) I was mangling the nickel silver rod. Once I allowed myself to accept that the rod was FUBARed I was able to use it to make a much better mockup, and that allowed me to see that it would have to be a two-piece rod to work as needed. No way around it. I have the long, central section locked to the piston set via two "pillow blocks" so it will not be able to flex to the side the slight bit needed to allow the stop arm to go past the stem, as that action does not actually have a straight path — it is a very shallow semicircle. To prevent the long, convoluted rod from flopping around and making all sorts of racket it has to be secured so that it can *only* travel up and down, and that precludes the action around the valve stem.

Solution: The short bit with the Minibal link on the end has to be a separate part, free to rotate as needed. Where the 90º angle occurs will be a wafer of .25" NS brazed onto the end of the long rod, which will be drilled and tapped like the stop arm itself. The rod needed for this bit is 7 mm of threads on both ends @ M3x0.5 with an 8 or 9 mm length between the two Minibal links. This will work very well. (I have made stuff like this in the past. It is a major PITA but if done right it works really well and is not slow or heavy-feeling.)

So in the pic, the red circles are where the pillow blocks will live on casings 2 and 4, and the rod will ride in them for alignment. The blue ends are the .25" wafers that will be tapped for the Minibal screws. The lower end will connect directly to the 6th lever via a Minibal on the blue spot.

I tried to make this short rod twice and this was the best I could manage. I need a lathe. This would have taken me like 15 minutes to make and it would have been exactly what I need. Note the lack of threads? Well, that M3x0.5 threading die took a walk on me. I have one on order and it will be here on Wednesday.

Why am I cutting down the rod rather than center-drilling and tapping the end for some all-thread rod? I need a lathe for that, too. My drill press is suboptimal in just about every category by which one would judge a drill press.

I will have a lathe by Christmas, though — I hope. My situation right now had me almost pulling the trigger on a lathe two months ago, and then the bottom dropped out on us again, and all that savings is burnt through, so I am starting over again. I will get it, though.

My solution for the short rod, since I have to buy two ridiculously expensive Minibal links anyway, is to buy the short arm kit from Instrument Innovations, which includes two Minibal links of the right size, two screws, and a nice, stainless steel connecting rod of 1.5", 1", or .5" (not including the threaded ends) and have him make the rod to the length I need. It is actually a little cheaper to do it this way than to do it myself, which is something that only occasionally happens.

So I now have the exact shape (torturous as it may be) for the long rod and an adequate solution for the short rod. Now I have to bend up my two levers so they do what I need them to do. I might have to destroy my nice 1st slide braze with the lever rack on it to change some things. This has been a genuine prototyping experience, with me having to do, re-do, and re-re-do my doo-doo to get it right. I have learned a lot, and the final product will be very nice. But it is costing me more than I had anticipated.

My final "final solution" is to eventually pick up two more valves, customized by Miraphone, so that they BOTH include ALL the things I need to make this work nicely. One day when I make that order, the levers will simply be two long, straight rods that run parallel on the same side of the pistons. Until then, I have to make do with what I ordered, despite my realizing that it was not really what I would need.

Again, prototyping means constant changes to plans as things are discovered. I now understand why it takes so long for tuba designs to move from the test phase with a solder-covered demo horn at TMEA until it is finally available for sale. Man, this it time-consuming work! But I get a kick out of it, to be sure.

The little, purple arrow shows how the end of this convoluted link arm has to move outside of what the red circles will allow. So that end bit has to be a separate rod that can pivot as needed. "It mocks me."


Despite the way the lighting makes the ends look swelled like little bats, they are actually filed pretty straight and even. Doing this work was a massive PITA, and I had to do it a few times to get it just so. And it is still UGLY work. So this will be replaced by the little assembly from Instrument Innovations.

[bloke]

… so I may have read an earlier post too quickly, but I thought you were going to do something so as you could somehow use this instrument for Easter Sunday. I would guess that you wouldn’t want to take it somewhere and use it as an four-valve - and I probably missed it in a previous post, but my guess is that you took your 186 (and I really couldn’t think of a better all-around church gig tuba) to play, today.

This organist (Memphis – quite a few Christmases and Easters in a row) likes “big bass“ tuba sound - and I was looking forward to a nearly immediate run with my new-to-me instrument, but he handed me a solid stack of (Richard Webster brass settings) bass trombone parts, so I didn’t even use the tuba (which I did drag to the rehearsal). I guess playing the somewhat-new-to-me euphonium on everything was a decent consolation prize.

Anyway, you’ll have that thing going really soon. If nothing more, I think we would enjoy watching/listening you play a chromatic scale on it down to the lower F - once it’s all hooked up. (It’s perfectly OK to make yourself a fingerings cheat sheet. )

…My new to me thing certainly needs a cleaning, and it also needs some alterations. No matter how expensive/touted/highfalutin, I’ve never owned a factory built instrument that was completely to my satisfaction. Of course, when we build something - and eventually proclaim that everything is just right - that’s kind of a “cheat”, because we ourselves can define when it is finished being built.

That handmade link connector is some fine handwork.

[the elephant]

I have the horn set up stock, five on the RH, and took it to rehearsal on Wednesday night. I decided with the pieces we were playing that the 186 would be "easier" to fill the hall with on the congregational stuff, so that is what I took today. It went great. I really love that tuba.

And that took the pressure off, allowing me to take stuff back apart to more easily work on this funky 6th linkage. The main benefit of this is that when I am done for the day I do not then have to wash out, reassemble, test, and pack the horn; it can stay on the bench all night and be ready for work the next time I walk in there. Doing long-term experimental work on a horn while you are in the middle of using it a lot is a drag. Switching to the Miraphone was the correct choice, I think.

[the elephant]

Today the new thread cutting die and handle arrived. Drill America — made in China, but priced appropriately. I have to say that this stuff was not impressive out of the boxes, but they worked great. I have bought odd-size drills from them in the past and was pleased with the performance, so this must be a decent importer, to drill bits and taps and dies and such like Mack or Wessex is to "other" (lesser) importers. I will buy from them again, and likely will continue to do so when funds are short until, of course, at some point, they let me down. Not a bad purchase.

I was able to thread my little nickel silver stub today. It came out GREAT. I am pleased enough to go ahead and make another out of non-trashed rod stock so that it looks nice. Truth be told, the tiny imperfections are such that NO ONE will ever see them unless I am dead, the horn has a new owner, and it is being serviced, and even then I think it will pass muster.

Buying an actual round thread-cutting die was worth it. I never get clean threads this easily when I use a hexagonal thread chasing die. The HSS of the cutter makes all the difference. The hex die's carbon steel is just too soft. Also, deciding to saw in a clean shoulder to the rod really made things neat-looking.

On to the long section of the linkage!

[York-aholic]

Me like! I had a similar situation on my Eb. I used SS 3mm threaded rod, then put a piece of brass tubing over the threaded rod, figuring that tightening the minibal ends up against the brass tubing would serve to lock things from working loose (as does the shoulders you cut.).

However, I think I like your solution better.

Will I ever get around to revamping mine? Hmmm... That's a whole 'nother question!

[the elephant]

Tonight I bent a new 6th lever… out of brass. It is a heavier gauge than the nickel silver one I bent the first time, and it is pretty rigid. I have the exact, same diameter of rod in nickel silver, so I will get this functional in brass (easy) and then sit down and make the nickel silver rod at a later date. Oddly enough, the stock 5th rod is made from the same size brass rod, from the factory. It has much larger Unibal links (
swiss-made, so that makes sense) and I like them a lot better than the Minibal links, but I cannot figure out how to order from them. Anyone from Switzerland reading this who knows what I have to do to get some of their Heim joints?

So I have a much more closely shaped rod now, and I did it without having to hammer on it at all, so it still looks really nice.

I also did my first attempt at the pillow blocks. I have the cut and pre-drilled. Now I have to "part" them into upper (non-threaded) and lower (threaded) halves, and then radius the bottoms and silver solder on some flanges to soft solder to the valve casings. Once they are on the horn I will "line bore" the two holes to the correct ID. I will have to make an extended drill bit for that, or maybe I can locate what I need at McMaster-Carr? Hmm…

The brass one is much more accurate, and I am pretty pleased with this one. However, this is all prototyping, and a little bit of each solution is guesswork, so I am guessing I will have to make two or three of everything before I get the 6th linkage dialed in the way I need it to be.


Everything about the nickel silver linkage arm is just a little bit off. Everything. But it was also mostly eyeballed, using some coat hanger wire as my initial guide. The brass one was made after comparing the NS one to the actual space on the horn. Things were discovered that allowed me to see small angular mistakes, and also in my plan for how this mess would be connected to the valves.


I had to alter the size and design of my "pillow blocks" once I had a more accurately bent rod to work with. These are my first (or likely several) attempts at this using my crappy, inaccurate, Chinese tools. I had to do a ton of filing to get these boogered-up parts to look this bad. You should have seen them at first. Whoa, Nellie…


I think I can make these work until I have a better idea of what will be needed. These do not look very nice and are not very accurate, but they are small, hidden, and likely never to be noticed, so I may keep them. Trust me, this was way too much work to toss out. These two parts took me two hours to make. Once I have a mill and lathe it will be a matter of minutes to make stuff like this, and the work will be a good bit more accurate. For now, this is the best I could manage, but I'll improve with repetition.

[the elephant]

MAYDAY, MAYDAY, MAYDAY!
WE ARE GOING DOWN!
FAILURE MODE ENGAGED!
SAFETY SQUINTS ENABLED!

EMBRACE THE SUCK!

Dang it! Well, these were highly inaccurate and flawed, and I learned a lot from this first pair. Now I need to get a new 6-32 tap (or three or four) and I need to cut two new blocks. I dug out my old Wen belt and disc sander (Hey! It's China-craptacular!), and the bed and fence SUCK! After about 15 seconds of light sanding to square up faces I would have to stop, unlock the bed, realign it, and relock it. Except that I had it so tight that it was about to break, and it slipped almost immediately once the machine was turned on, BUT it was nearly impossible to loosen the loose bed.

The Wen is great for woodworking as no real accuracy is needed when sanding stuff; close enough works well with wood. But that does not work at all with metalworking.

So I am partially out of commission until the 29th when I get paid again. Until then, I will make a new pair of these and THEY SHALL BE ACCURATE. Heh, heh, heh…

FML.


POS! I have "mad tapping skillz" and did everything right. However, this BRAND NEW tap was struggling from the get-go. The drill size (#36) was correct, but it felt like the tap was having to clear WAY too much material. And it was flexing badly from the start. This package was opened but stapled shut by our wonderful, local Ace Hardware Orcs, so it was likely used and abused a lot and then returned, and sold to me as "new". Jerks!


I have a lot of time invested in this little, ugly, inaccurate block of nickel silver. I also added to the wastage by spending an hour with all sorts of tiny tools trying to extract the tap's tip. No joy.


I believe I am on the right track, though. This would have made a very nice part. I think I will go ahead and finish it. One day it may get used, and I need to practice cutting it in half and then clearancing the outer half's screw holes and re-drilling the center hole (after the dimensional change from the removal of the saw's kerf.

[the elephant]

Me, just now…

[bloke]

I was dealing with a pos M3 DIE - when trying to finish up the Miraphone 84 #2.

I was quite disappointed with I realized that the S-arm linkage was toast.

When them thangs (at least) move, I can fix 'em...in fairly short order...and without having to "manufacture"...

...oh yeah: and they're purdy, too.

When stuff gets $h!tty, you need a catfish "therapy pond"...oh yeah...and some "therapy Malathion".

bloke "Ticks suck".

[Doc]

bloke "Ticks suck".

They certainly do.