Rekindling an old flame

[bloke]

Lime deposits can destroy nickel silver just as badly as they can destroy yellow brass, but in different ways.

Slides generally don’t get destroyed by nickel silver, because they are rarely moved, but rotary valves with nickel silver casings can be destroyed because lime deposits act like sandpaper, and just sand the rotary valve-to-casing fit looser and looser, over time. Even with lime buildup, oil can mitigate the damage, but those who allow lime buildup are almost always the same people who never oil.

Those who rebuild rotary valves with copper and nickel plating offer a valuable craft, but - because of the complex dimensions involved, their work is “handwork” much more than it is machine work, and therefore never offers as accurate a fit as newly-built rotary valves. The only way to rebuild rotary valve rotor-casing sets to a perfect-new fit - really - is to throw them in the garbage and replace them with new ones.

[the elephant]

Does anyone know, offhand, the actual desired length of a flat whole step 5th valve circuit?

How does 33 inches sound?

I got this out of a little demo program I wrote recently: Valve Lab. It originally didn't display the valve lengths, because it doesn't seem to me that this kind of simplified mathematical model is likely to provide really accurate lengths, but with that caveat, now it does - in centimeters. 1 inch = 2.54 cm.

The tuning I used to get that valve length makes 4-5 F a hair flat, and 1-2-3-4-5 Db is square on. The notes in between are a bit sharp.

@donn

I use 29" based on actual measurements AND the math, which, for me comes out to 29.55" and I round down. I want to be able to push in and pull out, so I look for the slide to be "set" for low F with it out about an inch. Since I am a big chicken I do not actually cut it that short, thinking that I can do so later if the circuit is flat. So what I end up with is a 29" circuit that plays low F in tune with 4th set up in tune for 24 combos, meaning that 4th is out a lot. I make 4th circuits about 61" in length and usually have the slide pulled three inches or so.

The stock Miraphone 5th routing is excellent as it has TWO slides, so you have a decent amount of pull in a very compact routing. The one @bort2.0 showed would be a water trap of epic proportions if the valve was in use a lot. And not purchasing parts is a misnomer since pretty much only the upper slide is retained, and none of the other parts are in the original 23 setup, meaning they all have to be purchased anyway (or scavenged). (I like the one bort showed as it is "clever" and I like "clever" engineering.)

I think just spending the money on the parts is not that much and will net a correct-length slide for certain, with no experimentation and assemble-disassemble-reassemble nonsense.

Here is a photo of the 186 flat whole step circuit, complete. I bought all these parts from Wessex a couple of years ago. They were inexpensive and are actually very well made. They are also very accurate copies of the Miraphone parts and (at that time) cost me about half of what Miraphone charged.



@kingrob76

• Nickel silver inner and outer tubes (only available in half-meter lengths, so you will have a lot left to play with) is about $60 for the two tubes. You will get all four short tube sets as well as all five ferrules, but they will not be decorated.

• Nickel silver upper and lower crooks together cost about $50 (keeping in mind that the nickel silver needed to match this tubas machine is about twice as expensive as the same parts in yellow brass).

• The "dogleg" and the "double knee" that connect the lower slide unit cost about $80 (again, yellow brass would be about half of this in cost, one part being about $15 and the other being about $25) which gives you the complete loop.

• The braces needed are two from the upper slide to the leadpipe, two to connect the lower slide inside of the valve section to the 3rd and 4th slides, and one on the outer side to connect the dogleg to the inner branch, so five in total. These are not inexpensive, either, as they are also in nickel silver. The set costs about $70.

The expensive elements (the valve and the lever/linkage system) are already present, so that saves about $400 off the top. You could get the needed parts — IN NICKEL SILVER — accurately sized and shaped to play in tune — for a total of about $260 plus about $65 shipping from the factory, for a grand total of $325 for all new parts that will perfectly match the tuba. Then you have installation costs. Getting the lower 5th slide to fit and work well between the rear valve caps and the inner branches takes some time, and fitting the two braces to the leadpipe is a PITA, too, if you want the feet of the braces that contact the leadpipe to not look like garbage. (The angle of the leadpipe at that exact spot varies from horn to horn and can be really difficult to work around.)

For under $350 for parts plus the cost of labor Rob could have an in-tune, modern flat whole step, completely "factory" 5th valve that matches his horn in every way except for the decorations on the ferrules and outer slide tubes. I have managed to add these details to my homemade 5ths and ferrules, though it took me way too much time. Using brass crooks and runners would save about $75 but would not match the tuba.

Also, Miraphone can sell the slide leg sets with the ferrules installed, the decorations being added for a small additional charge for labor. Going this route would cost more, but you would only be buying the very short tubing lengths needed and not half meters of the two sizes of tubing. I think that might even out in the end (in $$$ spent) and leave you with no fragile tubes to store away, probably never to be used. This route would match the horn perfectly and has some pre-assembly done, saving some time with the tech who builds the thing, so I probably would go this route in Rob's situation. I do not have prices or parts numbers for the pre-cut and decorated tube sets with the ferrules installed except for the main slide. (Sorry.) I do have the part numbers for most of these items, though, if you want them. Please feel free to PM me for the info I have.

Here is a photo of the main slide leg set I bought. It has the decorated ferrules and outer tubes, but has brass inner legs, as I ordered the set in this configuration. Unfortunately, I did not specify that I needed the old length ferrules. The worker, using incomplete information, did a great thing and included the 440 set of ferrules for me. He did not know these were being fitted to a horn that was nearly a half-century old, which uses the short ferrules, and he did a great job of fitting these. This means I could not remove the ferrules from the inner tubes. (You can see the heat blooms from my torch.) So I did not use this set on my 1971 186 and will use it on another project. My point here is that you can order from them slide sets like this in any metal configuration for any slide on the horn. This would make your tech much happier, I guarantee.



Here is my homemade 5th slide on my 186. It is not fully completed as it is missing most of the five braces, and it has not yet been cleaned up. I decided to bling out my tuba by using nickel silver slide crooks, which takes my machine closer to yours in attractiveness. I will be replacing more of the brass tubes with nickel silver eventually, but not for some time.

This shot allows you to clearly see the outer routing of the two slides and how neat the wrap is, with no water traps. It is an excellent, well-thought-out routing to replace the also-excellent 23 5th slide routing. The low F is not as amazing as the one on Rob's horn, but it works well enough. The difference in weight is only a few ounces; one cannot tell by feel in the lap which of the 5th slide lengths are on a horn. I like it. I copied it for use with a non-fifth rotor for my homemade CC 186. That also works quite well, since it is essentially the same routing. Joe did the same thing with his silver-plated 186 that Doc now owns. We adjusted things at the opposite ends for different reasons, but both got excellent results. The one in bort's photo seems like it would be sort of tight in response since it has two 1st slide crooks and a 5th crook rather than the more open single 1st crook and single 5th crook. It would work well but is also a bit more fiddly to assemble. The advantage of bort's example is that the tech does not need to be a stud to assemble it, as the difficult part (lower slide inside the valve wrap) is right out in front where it is easy to work with a torch and to clean up afterward. This means it likely would cost less in labor charges. However, it does not look at all stock. I got the vibe in Rob's posts that he would like it to look factory as much as it possible, so that might be a consideration.

[donn]

I use 29" based on actual measurements AND the math, which, for me comes out to 29.55" and I round down. I want to be able to push in and pull out, so I look for the slide to be "set" for low F with it out about an inch. Since I am a big chicken I do not actually cut it that short, thinking that I can do so later if the circuit is flat. So what I end up with is a 29" circuit that plays low F in tune with 4th set up in tune for 24 combos, meaning that 4th is out a lot. I make 4th circuits about 61" in length and usually have the slide pulled three inches or so.

I have an idea why I get larger values. I used pitch wavelength values from a table online, https://pages.mtu.edu/~suits/notefreqs.html, where C2 is 207.7 cm - a little over 17 feet, where the conventional length is 16 feet. I understand these numbers are both valid - the tuba is shorter than the corresponding wavelength for a couple acoustical reasons having to do with how the wave forms in a conical bell. What is not so clear to me, is which base value to use for the valve tubing - my guess would be the full wavelength, on the theory that those acoustical effects are pretty much confined to the bell and larger branches. It looks accurate enough on my BBb, though I haven't checked it out very thoroughly. [ edit ] Mixed results actually - the 4th follows the longer wavelength principle, while the 1st lines up with 18 foot and the 3rd is in between. So don't buy tubing based on my numbers - the point of the exercise was really just to render the effects of combined valve adjustments. [ /edit ]

[bloke]

CURRENT SIDEBAR:
sticking stuff together while attempting to pre-determine precise circuit lengths, and other digressions

The most accurate results seem to continue to be via trial and error.

Wade's "cut long" method is superior to most any other, in my experience.

"Planning out every last detail in advance" (when sticking together a tuba from old or old+new parts) has been my methodology in the past, but (with the one just completed (and I RARELY "do" these) "freestyling" worked out astonishingly well (as in: "Well, I'll be d@mned!" well).
Besides "using no mathematics - really - to determine circuit lengths", I actually had no friggin' planned-in-advance ideas of (even) where I was going to stick stuff - or even how I was going to get it there... ...OTHER THAN "Since this thing is so very short, I wonder if I can ALSO make it REALLY skinny - front-to-back (??)"
(Admittedly, I did have - from experience - some "It's going to need to be about like this, and - if more or less - it can end up within this range of acceptable positioning" thoughts.)

ALL of that having been said, I NEVER undertake one of these (200 - 300 hr.) projects without - AT LEAST - tooting on a minimally-playable mock-up of "the thing" FIRST, so I will know if "what I stuck together" will (at least) be saleable to someone else, if I end up being personally nonplussed with the final results.

[kingrob76]

I had a chance Tuesday night to play the 188 in an orchestral setting, reading Stravinsky Suite for Orchestra #1 and #2. Both pieces are rather unremarkable except for the solo (really a duet with the trumpet) near the end of the last movement of #2. It's a reduced orchestra, maybe 40-45 players total. Used a smaller mouthpiece and just sat back, kept almost everything no louder than a mezzo forte.

The 188 just locked in like it was being controlled remotely. It fit perfectly. There's a degree of precision with rotary valves that simply doesn't exist with pistons and that took a minute to flush out. I also took the 188 to a band rehearsal the day before along with my 6/4 CC and I found a preference for the bigger horn (largely because this is also reduced ensemble and I'm trying to build a "wide" bottom to the group) but the 188 was more adequate when I picked it up (albeit in a different way).

So yeah, the 188 - as I remember it - is definitely in the running for best "do it all" horn. Still very much one of the easiest horns to play I've ever encountered. My particular one, being gold brass, doesn't feel as broad as the one I owned 30 years ago BUT I suspect that is more influenced by my experiences since then than anything else.

[bort2.0]

^ That's extremely similar to my experience with my same-version 188. In orchestra, it was spectacular. In band, I wanted larger. I sold it, because I was playing a lot more band than orchestra, and frankly, I haven't played orchestra since then either. So... probably a good choice for me. But it's a tuba that sounds as pretty as it looks. :)