King sized tubing (.689)

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LargeTuba
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King sized tubing (.689)

Post by LargeTuba »

I would really like some king sized tubing (.689" I think). Outter tube, inner tube, and crooks would be greatly appreciated. In Silver would be super nice too. I think Reynolds tube would work too.

Also I need a .730 to .740" rotor If any of you guys have em.

Thanks :cheers:


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Re: King sized tubing (.689)

Post by KingTuba1241X »

How about .687''? Is there a difference? :popcorn:
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Re: King sized tubing (.689)

Post by bloke »

King and (pre-1980, full-size) Olds/Reynolds are the same bore (11/16" - .687"), but not compatible (different wall thicknesses, and will not fit each other).

You might (??) consider buying some 17.5mm (.689" bore inside/outside tubing from Meinlschmidt https://www.jm-gmbh.de/en/contact, if they sell it separate from valvesets...(??)
It will be nickel silver, and the base metal - then - would offer you a quasi-silver-colored appearance.
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Re: King sized tubing (.689)

Post by LargeTuba »

Im not super concerned about them being compatible, I just need enough tubing to complete a 4th valve worth of tubing.
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Re: King sized tubing (.689)

Post by the elephant »

He is talking about both the gap between the two tubes and the wall thicknesses of both tubes.

The gap is crucial, is tiny, and must be correct if you want to be able to solder things together. There are five measurements involved. The important one is the bore size, which is the ID of the inner tube. The wall thickness gives you the OD. The outer tube can only have a very limited size of ID — needing to be between two- and four-thousandths of an inch larger than the OD of the inner tube to be usable. A gap of .002" nets you a *very* snug fit, like what you need between the inner tubes, runners, and crooks and your connecting ferrules. A gap of .003" or .004" will give you what is needed for a pullable slide. The outer tube's OD does not matter, but usually, the outer tube is a bit thicker than the inner one.

If you want your 4th slide to be able to connect to your valve ports the tubes must be pretty close in these measurements or they are not compatible with one another.

By the way, BRASS (not silver plated and not nickel silver) matched sets of slide tubing for a tuba with a .687" bore are available from Allied Supply. The part numbers are K636 (inner) and K637 (outer) and the measurements are

K636 — ID .687" OD .718" (wall thickness of .031")
(Note that between them is a .002" gap!)
K637 — ID .720" OD .760" (wall thickness of .040")

Joe's suggestion of hitting up J. Meinlschmidt for a half meter each of inner and outer tubes for .689" (17.5 mm) bore valves. It will fit your valve ports, but you might want to expand them just a smidge so the new tubes fit snugly. The nickel silver tarnishes to a flat gray color, but when polished up is very close to silver in color, usually being a tiny bit more yellow or black, depending on the exact alloy. If you polish them up with Simichrome they will look very close to your horn, will be much stronger than brass, and will have a very low risk of red rot due to the lower zinc content.

For a 4th slide, you might need two half meters of each. (Half meters are much less expensive to ship than full meters.) If you get the much less expensive (about half the price) yellow brass tubes from Allied they come in like 30" lengths, so one of each would probably be enough. Also, if you need more it is easier and faster to get it here in the US, so screwing up your measurements and coming up short is less of an issue. Make that mistake with a company in Germany and you will have to pay a lot and wait a long time to correct it.

I hope this helps.

Best of luck. Please post photos of your work along with comments about what you did and what you learned along the way.
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