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I’m finally getting the gumption and have space in my shop to tackle two looming projects: converting a Cerveny 4v Eb to a 5 valve, and I’m also doing a frankenproject:

Olds O-99 (Bach) body
Miraphone 184 bell
Conn 14k valveset with added fourth from another 14k

The end result will be something like a piston 184 with a .734” bore. I may discover that bore is too large, in which case I have a .687” King 1241 set to use instead, but I’d really like to save that for the Martin Medium Eb project I have in the wings… I may end up using a 1240 3 valve set I have and pasting on the fourth from the 14k to create a graduated bore, we will see.

No pics now, but I have the Olds/Bach taken apart, and the 4v 14k valveset is assembled after much cursing and cutting and trimming and soldering. Next I will do dent removal and lacquer stripping of the Olds body.

The Cerveny project will be more straightforward, requiring grafting on of a fifth valve from donor horn, new larger receiver, dent removal, and putting modern linkage to replace the existing clockwork stuff.

I'd wager that it'll work out, as long as you don't ruin it by cutting it to C - likely, knocking all the partials out of tune.

bloke wrote: Mon Apr 13, 2026 10:47 am I'd wager that it'll work out, as long as you don't ruin it by cutting it to C - likely, knocking all the partials out of tune.

Don't worry. It'll B(B) flat.

I also have a spare Miraphone 186 rotor that telescopes decently into the .734" tubing, but I haven't committed to that. It'll probably just be a 4 valver.

Compared with the King 1241 valve block, the slide layout of the 14k section better matches the original Bach/Olds configuration, so I won't have to fiddle with geometry too much, except dealing with how to route the 4th valve. And I have lots of spare tubing to mess around with (essentially, three 14k valve blocks' worth).

After all this, I will have a spare Bach bell, badly crumpled and with a few holes in it, and the spare Bach valve section, which I sold bloke the pistons out of. I'll probably hang on to the valve section just in case I come across another Olds/Bach thing that needs spare parts.

Was the 184 bell from a CC or BBb, or are the bells pretty much the same?

Oh, and what happened to the rest of the 184?

York-aholic wrote: Mon Apr 13, 2026 1:37 pm Was the 184 bell from a CC or BBb, or are the bells pretty much the same?

Oh, and what happened to the rest of the 184?

I received the bell in a trade, so unsure what happened to the rest of the tuba. I think it was a CC, but it fits. It is maybe an inch shorter than the Bach bell with a bit less pancake, so I will probably have to have a longer tuning slide, but all that was going to have to be redone anyway.

Older 84 bells are taller and end up being smaller on the small end whereby the bottom bow is smaller on the large end.
Again, I'm referring to the older ones

I'm looking forward to seeing a frankentuba!

Tubajug wrote: Tue Apr 14, 2026 10:53 am I'm looking forward to seeing a frankentuba!

Thanks for all the 14K parts!

arpthark wrote: Tue Apr 14, 2026 11:06 am

Tubajug wrote: Tue Apr 14, 2026 10:53 am I'm looking forward to seeing a frankentuba!

Thanks for all the 14K parts!

I'm glad to see they'll get put to use!

The rub of this project is that the large end of the 14K tuning slide is way bigger than the Olds/Bach dogleg, so I am going to have to get creative.

Also @Casca Grossa, my goal is to get the Cerveny done by late June when I am driving through PA to KY.

arpthark wrote: Mon Apr 13, 2026 8:49 am I’m finally getting the gumption and have space in my shop to tackle two looming projects: converting a Cerveny 4v Eb to a 5 valve, and I’m also doing a frankenproject:

Olds O-99 (Bach) body
Miraphone 184 bell
Conn 14k valveset with added fourth from another 14k

The end result will be something like a piston 184 with a .734” bore. I may discover that bore is too large, in which case I have a .687” King 1241 set to use instead, but I’d really like to save that for the Martin Medium Eb project I have in the wings… I may end up using a 1240 3 valve set I have and pasting on the fourth from the 14k to create a graduated bore, we will see.

No pics now, but I have the Olds/Bach taken apart, and the 4v 14k valveset is assembled after much cursing and cutting and trimming and soldering. Next I will do dent removal and lacquer stripping of the Olds body.

The Cerveny project will be more straightforward, requiring grafting on of a fifth valve from donor horn, new larger receiver, dent removal, and putting modern linkage to replace the existing clockwork stuff.

I am so excited to hear that the Eb project is heading to the workbench soon. The franken project sounds very cool. I vote for the added 5th valve if you can make it work. The 184 bell is definitely from a CC.

Been pretty busy lately. Got all the lacquer stripped from this Bach/Olds body and worked on mocking up valve section. Just a little bit of bore distortion on attaching on the 14k valveset, but I was able to fit everything together, bugle-wise. I didn't even have to put on the King 5th branch like I was expecting.

Donor Cerveny is disassembled with the fifth valve ready to attach to the recipient Cerveny.

I also decided to straighten out this Martin Medium Eb I picked up a while ago. It lived a lot of its life outside. I didn't even have to unsolder the bottom bow when I took it apart. I got all the outer bows less of a D shape and more of an O shape, and smoothed the bell out very nicely.

The Martin bell is in very good condition. The body, meh. There is a pinhole in the first branch that I will put silver-bearing solder in. The dimensions line up very well for grafting on a King valve section, so that's on the docket. I'm pretty excited about this, because it will be a size sort of in between the 15" bell and 19" bell compensating Ebs, with a really nice and in-tune sounding bugle.

Other stuff... did some random/piecemeal work fixing a Bach Strad trumpet (stuck slides galore and dent removal). Chem cleaned an ancient, grimy "CADET" made-in-Czechoslovakia trumpet. Lacquer stripped and began fixing up a Bach 50BL (dependent rotor) bass trombone with an aftermarket Giardinelli split trigger for the dependent valve. Lots of sloppy solder and finish issues that I'm going to address, not too many dents, kind of rattly linkage to tighten up.

I've figured out how to configure the fifth rotor on top of the 4v block by using a donor L-shaped piece of tubing from the donor 1st valve and a donor 2nd valve slide. It will end up looking kind of like how five valve Alexanders look:



except the 5th rotor will not have an upwards-facing exit port.

Being an Eb tuba, there will be more clearance shown than in the Alex F, so it will be doable.

Most of this project, so far, is me staring at a tuba and pontificating.

arpthark wrote: Tue Apr 28, 2026 7:56 am I've figured out how to configure the fifth rotor on top of the 4v block by using a donor L-shaped piece of tubing from the donor 1st valve and a donor 2nd valve slide. It will end up looking kind of like how five valve Alexanders look:



except the 5th rotor will not have an upwards-facing exit port.

Being an Eb tuba, there will be more clearance shown than in the Alex F, so it will be doable.

Most of this project, so far, is me staring at a tuba and pontificating.

Oooh. This I want to see!

arpthark wrote: Tue Apr 28, 2026 7:56 am I've figured out how to configure the fifth rotor on top of the 4v block by using a donor L-shaped piece of tubing from the donor 1st valve and a donor 2nd valve slide. It will end up looking kind of like how five valve Alexanders look:



except the 5th rotor will not have an upwards-facing exit port.

Being an Eb tuba, there will be more clearance shown than in the Alex F, so it will be doable.

Most of this project, so far, is me staring at a tuba and pontificating.

Take whatever time you need to pontificate. I'm so excited for this project. I am more than happy to get this in my hands later rather than sooner to let you do what you need to. Post photos of the progress if you have time.