Kurath — Am I Finally Finished? NO!

[bloke]

Your 6-valve (will be short-lived) F unfamiliarity is similar to my (likely, never-will-quite-be-overcome) 5-valve+trigger F unfamiliarity.
When I encounter divergent valve combinations (B with 2-4 + 2nd slide trigger, range just above low F - with low G certainly requiring the 2nd slide trigger, etc...) playing the F cimbasso, I'll still occasionally write in the damned fingerings (along with a "T"). If such pitches are required over-and-over...no, I don't need to do that (ex: Verdi's Va, pensiero chorus from Nabucco...is that ten - or is it fifteen sharps, in the key signature...??), but when "licks" occur once or twice - which encounter those pitches, yeah...I might write the fingerings in...particularly if they are syncopated "rock" or "jazz" licks (where I'm both concentrating on timing and fingerings).

[the elephant]

I'll be performing the Broughton on this tuba on April 27th. Free admission.

[MiBrassFS]

.

[arpthark]

Great poster! Yamayork makes a pretty good background.

Good thing to have the rolled up sheet music at the ready, ya know, to ward off unwanted flies during the photo shoot…

[the elephant]

I have this disturbing Frasier Crane vibe going.

Just shoot me now.

[bloke]

I just shot E.M. a message telling him to find him or us any sort of an excuse for any sort of gig that pays anything at all so that I can tell Mrs bloke I need to go down there that weekend.

[the elephant]

After finally getting to give the 5th/6th valve system a good bit of use, I have decided that I need to unwrap one side of the lever springs one wrap to reduce the tension, which is way too strong for me to have any sort of technical facility down there.

Tomorrow.

Also, the upper 3rd slide needs a half-inch haircut to bring it up to pitch.

Later, but soon.

And I am beginning to believe that my 5th and 6th slides are finally settled in where they need to be, and I can take stuff apart and replace the legs with sets of the correct length. I will, at that time, realign the to rotors to allow the slides to fit in their space somewhat better and shorten an overlong brace, which will strengthen it a bit.

Also, I think I will make a new mute out of sheet aluminum that is a copy of my Ion Balu mute. It works well but is not buzzy at all, and I need buzzy, loud mutes for all my horns. If I do this and it works, I will turn the Balu mute into a practice mute. Or at least I'll try to do that. Practice mutes all pretty much suck, so whatever I come up with ought to be at least as good as anything on the market. The bar for practice mutes is set very low.

Finally, I have decided to remake the lever rack and baseplate. I will do this in the summer months. I just ordered a 125" thick 5"x10" nickel silver plate to cut up for this. I used a .125" 1.5"x10" bar to make what I have, and it was too narrow to put the lever rack far enough away from my hand rest to not have my fingers bunched up. What I have is too close to my palm for good technique. I will also use old Miraphone levers as they are just better than mine. The ones I made are very good, but the geometry is weird. (Too short, maybe?) I have ideas about what I need, and I will hack them out of that sheet of nickel silver in a few months.

So before the concerto I will adjust the spring tensions and trim the one slide. If I get around to it I will lengthen the inner legs of the 5th and 6th slides and see how I feel about them. If that is my final decision then I'll tear apart the valve section and install the outer legs to match.

Film at eleven! (That's a lie. There will be no film.)

[prairieboy1]

Thanks for posting! That is a terrific photograph of you!

[the elephant]

My longtime friend and colleague is the conductor of this group, and he needs a current Bio for the program. I sent him this. (Yes, I'll send him a *real* bio later tonight.)

Wade Rackley, a native of the Tamms Federal Correctional Center, was born in a log cabin he helped his father build. He never knew his mother, who left his father before he was born. Wade is a terrible person who is guilty of many felonies. Wade was the governor of South Dakota at some time in the past, under an assumed name. (No one noticed.) Wade appears courtesy of Gold’s Gym and Red Bull Energy Drink because he is such a BAMF. Today’s performance is sponsored by a big-ass grant from Swanson Hungry Man Frozen Dinners.

[the elephant]

It always pays to be curious and unsatisfied!

I worked on the springs of the levers for two hours last night. I thought I was going to ease the binding and tension of the 6th spring, and it ended up being SPRINGFEST-2025, which netted some excellent results.

First, I tried to remove the two levers and noted that the hinge rod/axle needed pliers to pull it out. No bueno.

Then I spun both levers on the rid and discovered that while the 5th spring was binding heavily against the lever rack, the 5th lever was simply not turning with a flip. With a backlight and some magnifying specs, I could find NOTHING. No schmutz. No particulate. No burrs.

<grumble>

So the next step was to whip out the super accurate mini drill press. This thing cost me next to nothing. It has no real guts for drilling, but it is perfect for shallow holes or opening up or cleaning out long holes, like short lengths of hinge rod. My big drill press has terrible runout in the quill, which is not a removable part on my cheap, Chinese unit. I junked it. This little baby is much more useful to me and has a very good Jacobs chick (made in Connecticut in the 1960s) that I restored myself. It features a fantastic .001" of runout. The Chinese unit has .011" of runout at the quill, so even a theoretically perfect chuck would still see all .011" of that runout, which is HORRIBLE. Introducing an average eBauy chuck to this would net you so much runout that you could see it from about ten feet away!

So I "reamed" the lever, and there was a tiny steel bur that had somehow gotten in there and then had been embedded into the softer hinge tube. (The rod is HSS drill rod.) I got the tube all cleaned up without opening up the hole, so the action has been returned, and the fit is the same.

Then I spent a long time uncoiling the ancient nickel silver wire springs, which are very stiff. I ended up having to unwrap about 2.5" of wire from each side of each spring, so TEN INCHES of wire was cut out…

… AND THEY ARE STILL VERY STIFF SPRINGS!!!

I guess I need to remove one more loop? Ugh.

But I suddenly have "technique" in the pedal register of the Kurath.

Cool.

That took so long that the intended slide trimmings did not happen.

Maybe today.

[bloke]

Yesterday, I spent 800 bucks on a proprietary double pulley for that ridiculous mower that you've seen, and I wasted 30 minutes on the way home at Home Depot looking for some common hardware for bifold doors that they did not have.

...so you did a lot better than I did.

[the elephant]

Again: no photos. There isn't anything to photograph during these steps.

Anyway, sorry for the length, but you know how I am…
_______________

Tonight, I decided that I will indeed take off one more loop from the lever springs. Great: something sorted!

Also, to avoid doing any work that might waste expensive material and valuable time, I dry-fit some bits to extend the overly-short 6th outer tubes so I could pull out beyond the edge of them.

BINGO! Low B (46) is solid, fat, and happy now. Low A, Ab, G, and Gb are likewise happier, and the low Bb and C are ecstatic because to get all those in tune, I had to pull 5th to compensate for my too-short 6th, making Bb (45) flat, causing me to have to push in on 4th, making low C (4) in tune, but somewhat less than centered.

All that is fixed now.

With this last bit sorted, the low register on this tuba is rockin' along far better than any Willson or Kurath of this design that *I* have ever encountered. I am quite excited about this. The tuba was really good when I got it, but the low Bb was barky, pinched, and difficult to center, and moving the slide did nothing to the pitch.

The issue was that the factory "mathematically correct" slide was way too short. Likewise, my 6th was cut to what is suggested by Art's spreadsheet and backed up with my own math. It, too, was short. [Once you get these oddball valve circuits sorted, things get exciting. I can play out of the Snedecor "Low Etudes for Tuba" with the same ease and facility as with my CC tubas.]

Tomorrow I plan to cut a new set of 6th slide legs. I have a problem, though. I've run out of the tubing needed for the outer slide tubes. I have more than enough of the inner material, but only enough for one outer leg and the needed ferrules.

However, I have some MW telescoping stuff that is not exactly the same size, but is *very* close, so I think I will fudge a bit and make one leg (inner/outer/ferrule) from the same Miraphone stock that is on there now, and the other set of parts from this MW stuff. It is too large for the crook and runner ends by .25mm, meaning a slightly loose fit. I can EASILY bump up the crook and runner to fit nicely, so no issues. My problem is that I detest mismatched tubing sets.

I can always swap them out later.

I guess.

[the elephant]

I decided to leave the 6th slide as it is for now (slide, two loose spacers, two loose ferrules) to test it out at work tonight. I have the Rachmaninoff Piano Concerto No. 3 — the big one — which has an easy tuba part with a lot of low Bs and As that will allow me to fool around with this setup in the ensemble before committing with the torch and solder.

More later…

[the elephant]

My big-a$$ nickel silver plate arrived today from Jantz, so I can finally remake my lever base plate so that the levers are in a little better location. I have been buying from them for years now, and they only ever offer 1/8" thick metal bar stock or plate in sizes that will net me a part that is a compromise of what I want and what the part can yield, or I have to buy more than I could ever use. No in-between. So now I have a lifetime supply of 1/8" thick nickel silver.

Luckily, I think I will be making something like this lever system for the Holton, so I will probably use up a lot of this in the end.

By the way… this sheet of metal is surprisingly heavy. I mean, dang…

Also, I used the Kurath today in the quintet and on Monday and Tuesday in the orchestra. 6th is nails, baby. Nails. Playing the transcription of the Holst 2nd Suite in F that we use was a lot of fun. After the trombone plays the euph solo, the tuba part is solid half notes below the staff in the tricky area, and every low Bb, A, G, and F sounded full and in tune, speaking without slowness or "flarpicity".

And at this point in the post, a whole dissertation's worth of my hairbrained ideas on this tuba were typed, edited, retyped, reedited, and — finally — deleted.

And for that, you're welcome.

[the elephant]

Okay, so my cheapo, lightweight link arms on 5th and 6th are a design that works well enough when the length needed for something like a 186, but these 12"+ links do not work. Well, not exactly…

The original 5th linkage was a 6mm (c. .25") yellow brass rod with large Schaublin "Unibal" end links. Very heavy, but only about nine inches long. Solid as you would expect from this maker.

I had issues with my original, funky 5th lever — its length and shape caused it to flex all over the place. It was expensive as I wasted a lot of nickel silver rod stock sorting this problem.

I switched to some machinable, bendable stainless steel rods. They bent well enough, but once bent, they were work hardened enough that you could not unbend (adjust) them. To make my ideas come to life, the shapes kept getting ever more complex, and I would end up snapping these steel rods on tight bends. It was frustrating.

First, I ordered new, custom-made valves that simplified linkage routing greatly, and second, I switched back to nickel silver rods. In the end, the new balves allowed me to go back to (thankfully) STRAIGHT rods, so the material no longer mattered that much. Because they had to be more than a foot long, though, they were very heavy, making valve action pretty sluggish. So I opted for some super-lightweight rods. For 6th I used drill rod inside some very thin brass tubing, which worked really well, but is rather noodly feeling as it flexes visibly when used. For 5th I discovered that I no longer had enough of the drill rod, but I had some 12" lengths of 4-40 all-thread. So I used the same thin-walled brass tube (we're talking paper-thin) and ended up with some good link arms. But the all-thread is only about 2/3 the weight and thickness of the drill rod, so it is VERY flexy, and the threads would buzz and rattle against the wall of the brass outer tube.

My solution was to fill the tube with blue thread locker and run the all-thread into it while it was wet. It worked great.

Then the other day I had to remove that link arm and it flexed hard while I was snapping the sockets off the balls. Now it buzzes like a 1970s Panasonic clock radio alarm while I play. bzzzzzzzbzzzzzzbzzbzbzzzzzbzzbzzbzbzzzzzzbzzbzbzzzzzz…

It is driving me nuts, man.

so I decided to see if I could locate drill rod locally, had little to no luck, and do not really trust the stuff at Home Depot. So I am back to nickel silver. I have two rods of equal weight that are light enough, so rather thin, but usable. I will have to machine the ends and thread them in the lathe as they are to big to thread directly and too small to center drill and tap for threaded inserts. I will have to turn down the ends and run them through a die.

Only issue: Both are about an inch too short.

Sheesh.

So I may keep the drill rod arm and ditch the outer sleeve, and then make a temporary arm from the HD steel rod to replace the all-thread arm, which will likely be overly soft, prone to rust, and irradiated or toxic crap from China, and hope for the best until after the 27th, or I can maybe figure out something else. But what I have right now must be replaced ASAP.

Here is what I have. The brass rod is a eggshell-thin brass tube with smooth drill rod inside. The other is all-thread with the same outer tube (not present in the photo, of course). The threading makes the all-thread very bendy and weak, which is why the brass tube is there: stiffness, but it does not work on something this long.


Better videw of the two rods when fully assembled.


Also, I have removed about three wraps from each spring coil to make this suer-stiff nickel silver wire a bit more forgiving to my weaker, untrained left hand. I have discovered that using these in the Broughton is really tiring my hand out. I need to do such work more often. I have never used my left hand for valves, and it really shows after a four hour practice day. OUCH!

[the elephant]

I have decided that this is the summer when I finally finish the Kurath.

I have been playing it for some time now in its current state and feel that I have it pretty well dialed in, have the exact mouthpiece I want to use on it, etc. Now I want to "prettify" it so any future owners will have trouble figuring out exactly what is not from the factory.

This summer, I plan on making new levers and linkages that are mounted on a much nicer-looking bracket, and that will be very labor-intensive. I have the nickel silver plate from which all the parts will be cut, and it ought to be easy, if somewhat tedious and slow-going.

I need to do some work cleaning up mount points for things that no longer exist. (For example, I have a bracket to mount a thumb lever, but I do not have a thumb lever anymore.) All that mess will be cleaned up.

I believe I will run the bugle (which on this tuba is just the bell, the bottom and top bows, and the dogleg) through the Z-60 to (as Joe likes to say) slick them out. Then I plan on buffing and lacquering the assembly using my automotive HVLP spray rig. I might do the valve section, but probably not. I will do all the bits that come off, though (leadpipe, slide crooks, valve caps and buttons, etc.) and keep the nickel silver outer slide tubes polished. I will let the few brass runners and the piston case stay raw brass to make it easier to work on. That is very little to care for, allowing easy access with a torch… ideal for me in my situation.

One thing I have wanted to do for a long time is make the rotor section removable, as it was on the Holton. On this horn, with its wrap, it will take some different solutions to make that work and have it be sturdy enough to not get pranged out of alignment. And it will need a union between the pistons and rotors.

Since Conn-Selmer discontinued the three-piece component that I had planned on using for this, I was left with fabricating something, and all I could make would be one of those split collars with the wingnut, like you see on sousaphone necks. I don't like those for several reasons. So I put this off while I decided how to use my lathe to make one like the Conn parts.

When I was flirting with a 6th valve for the Holton 345, I actually built the valve/slide circuit. To shoehorn it into the very limited space in which it was to live, I needed to shorten the union between the 5th rotor and the first branch of the open bugle. I ended up getting a used leadpipe union from a YBB-641, which I knew would have to be bored out a bit to work. (A lathe project?)

It did not look promising in the photos, as these always seemed to be pretty cheap and thin, primarily used to speed assembly at the factory, not intended to be used more than a few times before it broke or bent. Having never taken one apart and messed with it, I had no idea how incorrect I was in that assumption. It is actually more robust than the Conn part. I still do not like it as much, but it is by no means the junk I had always assumed it to be.

So I bored it out to accept the Miraphone tubing it would have to be soldered to.

Done.

Now it is sitting in a box, unloved.

I have written about the Miraphone system of bore sizes and tubing wall thicknesses in the past. They only use tubing from within that system; they only need to draw those and keep them in stock. Despite this economical way of doing things, they still have many different sizes because the make trumpets up through very large bore tubas. Rather than describe all of the ones I need here by the various bore sizes, I will write about them as I think of them when I work. Everything is based on the 186 tubak, so keep that in mind.

186 — No matter how the advertising wonks at Waldkraiburg want to spin it, the 186 and 188 are .769" in bore size. Where they got .772" is anyone's guess, but it probably involves a hobeful bit of rounding and massaging the metric size upwards to make people think it is bigger than it is. However, the difference between the claimed and the actual bores is almost nonexistent, so again, it is a bit of fantasy on their part. The ACTUAL bore size as indicated on the labels on the tubing is 19.54 mm, which is dead on .769". So no arguing with me. I am correct, as this is the label provided on the parts by Miraphone. The bore INSIDE the valve is actually smaller, as most people know, so don't toss that one out for discussion.

Okay, with that having been dispensed with…

The 186 uses three tubing sizes. Their part numbers and sizes are:

003612200082
ID - 19.54 mm (.769”)
OD - 20.32 mm (.800”)

003612200083
ID - 20.35 mm (.801”)
OD - 21.22 mm (.835”)

003612200084

ID - 21.26 mm (.837”)
OD - 21.93 mm (.863”)

The 6th valve I made for my Kurath uses a custom-made valve based on the 186-sized model with a larger exit port. The 4th piston uses the same size of tubing, and the 19mm ports have been expanded by half a millimeter to accept the Miraphone slide tubing. The exit port has also been stretched like this. The 5th comes next and is one size larger.

So 4 and 6 use the first two of the tubes listed above. To keep all the tubing straight in my head, I have "named" them by the last two digits of their PN. So the 186 uses tube 82 for inner slides, and 83 for outer slides. The MTS uses 83 and 84 for the tubes. And my Kurath uses 82/83 for the 4th and 6th slides and 83/84 for the 5th slide. (I used 84/85 for the small side of the MTS.)

The Yamaha union is for the 641, which has a bore just between two of the Miraphone tubes, so I had to bore it out a bit to use it on the Holton for the 6th slide. It is the interior size of tube 85, so it is like a ferrule to go over an 84 tube or valve knuckle. I need one that fits over an 82 tube (the inside slide tubes of 4 and 6, and the exit knuckle from the piston set), so to use this union, I need shims, and that sucks, because one shim is a PITA, but two will be a MPITA.

However, I figured out how to silver solder all that mess together so that there are, effectively NO shims. I was thinking of this backward and… well… wrongheaded. I thought I would have to carefully measure and cut the shims, clean and prep them for silver soldering, then do it all at once, which invites all sorts of nonsense.

Instead, I will use a hunk of 82 that is about 2" long and a shim of 83 cut to the needed length and silver solder these together first, then slide the Yamaha union half over that and silver solder THAT in place, cutting it off flush when it cools and has been through the pickle solution.

Silver soldering three super-thin tube ends stacked together would be difficult and require quite a bit of heat using my setup, and it would be for long enough that the union halves could warp. I have had better luck over the years, silver soldering tubes together if the ends are NOT flush, but when the inner tube extends beyond the outer, giving you an edge for the solder to flow against as it is drawn around and into the joint. If I build this from the inside out, the union parts only have to be heated one time each. Then hack off the ends flush. BOOM. Done.

The interior gap is about 1 mm larger (a 0.5 mm lip all the way around) and is very short. I may leave that, or I may make shims for that, too, but that becomes another PITA, so probably not. I have to feel it with my fingers to see what I want to do.

In the end, the Yamaha three-piece leadpipe union will go where the ferrule is in the red circle.





Making the rotors a separate assembly will make working on them much easier and faster. It will allow me to remove several assembly compromises I made to allow for work on the pistons. These will not be needed if I can simply remove the rotors altogether.


I pulled the needed tubing bits and have to unsolder the union half from the rotary valve that would have become the 6th valve of the Holton. I can use that valve/slide assembly for something else, someday. Once that is free, I can get to work making this necked-down union that will make all of this possible. I may even have the correct pin spanner here in my lathe tools for this union. If not, there is always Macmastrr-Carr…

[the elephant]

Lunch break…

I have one end done. It was… tricky. I figured it out, and the other will be easier.

Test fit and check to see whether the ends are actually flat and will have no internal gap. All good…


Slight ridge, but there will be another tube inside to take that up. Nice, flush end, though…


This shows one of the two shim joints, as well as the fact that the heat did not damage the threads of the union half.


A little bit of sanding to clean that bit up…


In the vinegar, dissolving the flux "glass"…


After lunch, I'll trim the end off, and that will be it for today. I have to remove the other half from the valve and spend time getting every tiny bit of lead out of the joint, or the silver solder will not flow into it. Less than fun. I'll have to turn my music up really loud to compensate…

[the elephant]

It is time for supper. I am finished with this mini project and am ready to convert the rotary valve section whenever I have the time.


That is a 186 inner slide tube (#82 @ 19.54 mm) on one side and a #84-sized (@ 21.26 mm) rotor on the other. (Prior to my having removed that half of the union assembly from the old valve.) It is a perfect fit now on that end. I then did the other end. This, also, was a very nice fit. None of the four shims can come loose if I ever hit this with a torch because they have been silver soldered in place. (And they do not leak.) The most time-consuming part of this was hand-sawing the ends off after silver soldering the tubes into the union halves using my jeweler's saw. That sort of sucked.

[the elephant]

Final fitting done today. Only took me hours and hours. Here is why…

I had to silver solder a shim to another shim. Then I had to fit that "stack" into the part, which took a ton of scraping, filing, and sanding to make the Yamaha part accept the Miraphone tubing. Then I had to silver solder the shim "stack" into the Yamaha part. Then I had to use my tiny jeweler's saw to cut off a double-thick tube flush with the end of the Yamaha part.

Then I had to do that again,

That was the other day.

Today I had to scrape-and-sand-and-file to get the Miraphone tubing to slide freely through the assembled Yamaha parts and correct the internal bore (which was like .812" or so, and is now .769"), and then lap the insides of the Yamaha parts until the Miraphone and Kurath valve knuckles fit better. (They are thick and, therefore, too tight.) Now they will fit nicely with enough gap for solder, but with no leaks.

This was an overly complex, unfortunate project completed due to the correct part not existing, so far as I know. I am glad it has been truly completed, and I can move on with my life again. What a PITA!

I own a nice lathe that could have done most of the grunt work in about half an hour. I did not remember that until I was finished, turned around, and hey, there's a freaking lathe…



Anyway, it is done, and it looks and functions great.

So whoop-de-doo.

Time for supper.

I really need to remember that I have a lathe, now.

I had a side debacle locating the thread pitch of the tiny screws that Miraphone specs for these tiny Minibal links. Apparently, they have used two over the years. Nowhere do my old invoices or pack lists include this info. Neither does the website. And the cute Miraphone-branded Torx driver that you can get ALSO is not labeled, so I had to get out a jeweler's loupe and a bright light and examine the driver against my set of tiny electronics Torx bits.

Answer: These are T6 screws.

Knowing that and using the brain-damaged AI that Google inflicts on its users, I micced out the screws and used the T size and the major OD to determine that I needed to buy a 1.6mm drill and an M2 x .4 cutting/forming tap. (FYI — Try to avoid using Irwin/Hanson taps and dies if you are cutting thread,s as they are described by the company as being for thread chasing, not forming. If you use a small one to cut threads and it snaps, they don't GAS, because "You were warned." I don't think this used to be the case, but it is now, and I won't buy them anymore.)

[the elephant]

Internal step added.

It did not fully fill the void created by all of my shimming work to adjust the ends to fit 82 tubing. But it is much better now. I will call this job "acceptable", but I am disappointed that common sense eventually kicked in to tell me to switch off my OCD…

I'll take what I've got. If this introduces weirdness, I'll know where to look. And it is a snug press fit, so I can easily redo it if needed.

This is the little bugger…


Note that it protrudes into the other half to fill the same void on that side. Ain't no way I'm gonna make one of these that is 2 freaking millimeters wide! My funky way works just as well and took half the time.


Two tubes with an 8 mm gap, but no internal step, baby. It's Miller Time!