The Great Kurath Re-Tubing

[the elephant]

Yeah, when we played that for the MSO audition that was on the list. I have only ever done it on CC but really wanted to use this "F BAT" because this part swings to this tuba's strengths — and I would have ample opportunity to use the 6th valve with all the low As and Bs and such.

Whatever. The 186 will rock it and won't be too big.
___________________

Today I installed the new rotary valve section, then took apart the MTS, measured once, did the math wrong, measured twice, F-ed it up again. figured out that the short side needed to have 7mm more cut from it than the large side, redid the math, yadda, yadda, yadda…

In the end I measured five times and cut once.

<phew!>

I had to trim 23 mm from the small side and 16 from the large to account for

• added length of the inside of the 6th rotor
• added length of the 6th rotor casing
• a 10 mm-per-side reduction in MTS length

It needs a lot of braces and a modification to the 5th stop arm to be usable at work. A lot more has to be done to get 6th hooked up, though.

[Sousaswag]

I've loved following your post, Wade!

I also love it even more now that I've purchased a very similar tuba to yours and seem to dislike the same weird Willson design choices that you do!

I would *love* to add a 6th valve to mine similarly to what you've done here; I think your ideas are so well thought out and executed wonderfully! Maybe someday!

Can't wait for more updates!

[bloke]

That weird glob of mess looks darn handsome on there!

[jk]‘ gotta mount those valve caps on your lathe, and face cut that ornamentation off those Miraphone caps… Kurath is utilitarian - though a six-syllable word seems awfully long, to describe something that is truncated. [/jk]

bloke “so does truncated”

… and – on other pieces – I still predict that you’re going to like the low G even more than you are looking forward to liking the A and B.

[the elephant]

• 5-6-3-4 low G
• 6-2-3-4 G♯
• 6-1-2 alt for 23

Thanks!

I have so far figured out

• 46 — low B
• 45 — low Bb (well, duh)
• 456 — low A

I will get your three suggestions some play soon. I hope I have the slides cut correctly. I don't want to have to remove, disassemble, trim (again!), reassemble, and reinstall this again!!!

So far I am pretty stoked about this modification. Not only are the low B and A more in tune, but they are more open sounding, better matching the low Bb. Prior to this, neither of those notes used the 5th valve. I used 24 and 234 as you would expect. The B was quote sharp. When lipped down it became very thin, and pulling was a PITA. The A was quite flat, requiring a slide push that I hated doing. I can't wait to get this into an ensemble to see whether it is as good as I think — or that I may have screwed something up and need to go back in, so to speak.

The low Ab is normally played 1245 with 1st pushed all the way in. It *must* be in or it is stinky flat. I am looking forward to trying out 2346, too! My low G usually is 2345 and is flat, but for some reason, the Gb creeps up so much that 1345 is just fine. I can't wait to see how the 3456 G is. And 126 for 23 will be fun to fool around with. Thanks again!

[the elephant]

… those valve caps…

No way! Those caps add to the "sexy quotient" of all this work. HAHAHA!!! I am excited to finish the pimping out of the slides by replacing the two 4th slide assemblies with my new ones. That ought to do it. Then I can clean up everything and BE DONE with that project — A-freaking-MEN!

I am a little stressed about rerouting the 4th circuit, but I may try to copy the one his 3400 Eb uses, which uses many of the same parts with valve porting that matches what I have. I mainly need to raise up where I rest my wrist (on top of the big 4th hoop) which is about 2" too low to be comfortable while using the 1st slide. If I do this I have to go all-in because the twin lever setup I will use for the rotors will be mounted at least partially to the tubing in this area, whether his or mine. A 2" move to the north will greatly affect the levers and linkages.

[the elephant]

I managed to do all the drek needed to modify my Miraphone stop arm to work with the Kurath linkage, so I once again have a playable tuba. The 6th is there, but not hooked up. I can easily rotate it with my left-hand fingers, like an old school Bb/A trumpet, where the rotor is simply an on/off switch you turn manually.

I have my 6th linkage arm mostly worked out.

The video shows the stop arm and the coat hanger 6th linkage mock-up.



And here are some stills…

It looked like I eyeballed it dead straight. I was wrong. But, while ugly, it is strong and works very well. I will re-do this when I make a new thumb ring and lever. Until then, this stays put.


Er-um-uh… something like this…


Slap a Minibal on that puppy and call it done.

[bloke]

You be way fancier than me is.

I use 3mm stainless steel rod, because it sorta stays shiny, I can easily tap the ends with the M3 x .5 thread, and - being small - it doesn't weigh much (ever so slightly less spring tension required...or even more than "ever so"...??)

...but yours looks much more cool, and matches up with the "Swiss/sturdy!" theme.

[the elephant]

… "Swiss/sturdy!" theme…

No sh¡t! This tuba was on its bell on a slightly sloped, polished concrete floor at an elementary school. We were not centered on our audience and were in the middle of grabbing our stuff and scootching over a few feet. In this short time when I took my hand off the tuba, it fell over onto the cement floor with a metallic BANG!

No damage whatsoever. Nada.

I like my super-lightweight tubas, but there is a lot to say in favor of that "Swiss/sturdy!" theme you mentioned.

I spent the last hour playing it, discovered that my 6th is *still* a bit flat, then realized that all my yanking of 4th was no longer needed. I pushed it in about 3/4" and BOOM the horn fairly rocks!

I have to use 6th with my fingertips, but only need it for a handful of stuff on the first three pages, and — to be totally honest — It makes the rather boring 1st and 2nd movements much more entertaining to play.

Adding that little twist to the open horn (inside the 6th valve) seems to have added a small bit of resistance where it was needed, so I can play now this tuba with my Stofer Geib and it sounds great up high. This mouthpiece change really opens up the low register, so the horn sounds more even from top to bottom now.

OR IS IT ALL JUST THE PLACEBO EFFECT?????????????????????

[prairieboy1]

Excellent! Good luck with it tonight!

[the elephant]

I got the information I needed, and the horn works more or less like it seemed it would. There were a few oddities, but I will chalk at least some of them up to my not having spent much time on this horn before toting it to work.

Joe, you're right. I will use my Miraphone 186. It just fits better in this piece. I had to work to get this horn out there at the end. Other than that it is just fine; I just don't want to have to work so hard.

Tomorrow I will be mostly making drawings of how the levers will need to be attached and then looking to source the materials needed to fabricate the parts.

Goodnight.

[York-aholic]

If 4+2 better than 5+1 perhaps better described as 4+1(+1) ?

Just curious.

I bet that was not a pleasant couple of seconds as that horn fell over.

Glad it wasn’t bent but, fortunately you ‘know a guy’.

[the elephant]

It will be 4+2 *and* 4+1+1, which is the beauty of it.

All of this started because

• there was this mysterious space where a 6th could be installed
• I had an F with LH 5th that I converted to RT, but left the LH gear installed
• there was a that could allow for LH levers without losing easy access to the 1st slide
• a "certain bloke" made me rethink the function of a 6th valve (as a CC 2nd valve)

I am a design opportunist. I am not sure I would have tried to add a 6th valve to this unless all these things had not been staring me in the face for a number of years. When I was re-tubing this horn I seriously looked at that "mysterious space" before I knew it I was mentally routing levers and such.

Then the fateful email to Miraphone asking about the custom valve that would make it all work nicely.

BOOM…

[the elephant]

I must use this emoji right now.



Our local McDonald's cannot produce or sell anything that is remotely palatable… except for coffee. The kid who runs the coffee bar thingie at our location is a demigod of the Bean Juice.

My wife just got back with our morning supply of this wonderful rarity and I am currently slurping it up as fast as I can without scalding myself. MAN, THIS STUFF IS GREAT!

Yazoo City McDonald's — you are one of the worst locations I have ever had the displeasure to encounter, but your coffee is divine. Give that kid a raise and fire everyone else. Stop attempting to sell your burger-shaped objects and just sell coffee.

[bloke]

> location location location <

Just the fact that we have coffee in our bedroom at 6 AM every morning seems to make it “wonderful“.

There’s a pretty nice modern-era coffee maker in the kitchen, but - in our bedroom - is an early 1970s stainless steel percolator connected to an early 1970s analog aquarium timer.

[the elephant]

I spent like an hour on these crappy, bent-up Italian horn parts, drilling everything out to fit the size of drill rod I want to use for my hinge rod. I had to order two suspiciously Bach-looking thumb nuts for the ends. I mean, they really look like Conn-Selmer orders them from McMaster-Carr. Wow. So that nifty design used by Bach since Moses walked the Earth is simply something that has been in common use forever. Even if they make the part themselves, it looks like Mr. Bach just bought those 3rd slide nuts from his local Ace Hardware.

Here is the 5th/6th lever rack that I will end up using, more or less where it will live. I am currently working out how to attach it so that it is 1.) sturdy AF, and 2.) removable, and maybe detachable from the bell end so that it is removable with the valve section. Taking all this off as a complete unit would be a great thing…

[Doc]

OR IS IT ALL JUST THE PLACEBO EFFECT?????????????????????

Let us hear it so that the TFFJ can give you its collective expert opinion.

[the elephant]

I received several messages regarding this lever rack. (For whatever reason, some of you folks will ask all sorts of questions privately but would never consider asking publicly. Either way, I have to answer you. Why not just ask in public and then everyone reading can think of the question and consider my answer. As it is, if I get enough of a response privately I have to answer each person individually, then — to PREVENT more of my time being eaten up with individual responses I have to address it in public. Please ask me stuff in the thread (or the Comments section on Facebook) as it streamlines the time I use up to post all this. I don't think a lot of you have any idea how much time is taken from actual work to document everything in the three places I post. Thanks for your consideration in this.



Okay, so today I decided that the Allied hinge rod, which is raw stock and not hardened at all. Miraphone hinge rods are (or were many years ago) somewhat hardened. The old ones are not so easy to booger up with pliers. (I have never had to go after a newer one, so I do not know whether this is still true.) The stuff Allied sold me rusts and is VERY soft.

The rod used in the Italian lever set is thin, worn, and soft. The Allied stuff I replaced it with yesterday is also easily bent and marred. (Again, it also rusts easily.)

I have an old 186 paddle hinge rod that had both threaded ends snapped off — to my eyes, brittleness indicates it was heat-treated to increase the surface hardness. Yes? No? I don't really care. It is stiffer and is more difficult to gouge or scratch with tools. Since this is a load-bearing piece I want these characteristics over the craptastic rid that was in this assembly. I do not want the Allied stuff as it is just about as weak and is not much thicker.

So I started over.

I drilled out the levers and the paddle rack again, moving up through the Drill Index four more bits, one at a time. The end result is a tiny bit more play between the levers and the rod, but it is just about imperceptible. That rod is metric and my Drill Index is SAE, so there is no perfect clearance drill for this. However, the whole assembly feels *better* with the heavier rod. It is less spongy (for lack of a better word).

Is this placebo effect in action? Probably so. Keep in mind that the rod *is* stronger, so whether I *feel* that or not is irrelevant. It may just be that the fit that I see as looser is actually better. I don't know. I don't have an engineering degree. I have a tuba degree. I am an engineering zero. Whatever, I like this better. It "inspires confidence". HA!

Here are some close-ups.

The top one is the old 1960s-era Mirafone hinge rod. I did not have to clean it up much. It just looks that good despite decades of abuse. The bottom is the old 1930s-era Italian steel rod. There is a small but definite difference, with the tuba rod being beefier, as one would expect. But it is also of a higher grade of steel.


The paddle rack holes all were wallowed out, and one was off-center just enough to flex the rod. I used a long drill bit to sort of "line bore" the three holes correctly. Now, with centered holes that are not all rounded off the larger rod fits very nicely.


My taps suck. I need to get the lathe paid off so he can deliver it to me. (Yeah, I bought a very small but very accurate benchtop lathe recently, but it will be a few more months before it is fully paid off. It was not cheap.) Once I get it I can do much nicer threading jobs than the crap in this photo.


I have a video coming up that will open up something for debate and suggestions that I am very interested in reading. It involves the platens (the flat, paddle part of the levers). It ought to spark some conversation on Facebook. I hope it will do so here, too. I will post it later.

Adios, y'all…

[the elephant]

Two videos.

The first is a 7:40 attempt to explain what I have been going on about. The second is a sub-one-minute clip that shows a bit better how the levers will be mounted.

[the elephant]

Thanks, McMaster-Carr!

I imagine that Mr. Bach must have bought these from some local industrial supplier way back when, and then perhaps he copied it. Note that several times over the past 25 years people at the company — on the telephone to me — have called this thumb nut design a "distinctive part of the Bach Stradavarius line" when it actually is someone else's design.

I need to trim the rod a bit. I purposely measured long because the actual Bach part has a LOT of slop in the threads, so I did not know where exactly the new nuts would end up. (The slop is bad enough that the Bach nut screws onto this rod about two full turns onto the unthreaded part. Since these fit exactly I can thread the rod a bit more and trim off the excess length.)

[matt g]

Getting there!