Bart Naked

[MartyNeilan]

BART is ready for the valve transplant, using a MW "small piston" .748-.787. cluster.
The old kaiser bore fourth valve is going to become the new 5th valve, either cutting the circuit to a sharp two-step or cannibalizing tubing from one of the removed valves to make a flat wholestep.
The leadpipe will be cut and rebent to go straight into the first valve.
I will make a dogleg going from the fourth piston to what is now the fifth rotor, using either discarded tubing from the cut-down fifth valve or what was cut off the tapered big end of the leadpipe, partially depending on how much I ultimately shorten the leadpipe.
I will raid one of the local hobby stores to make a new linkage for the fifth valve.

BartNaked2.jpg

BartNaked1.jpg

[MartyNeilan]

Where's the piston valves?

On their way.

[Bob Kolada]

I sure do hope that horn's a player before (if so, then why?) and after...

[JohnSzkutko]

LOL, "bloke" has a lot of spare time on his hands

[imperialbari]

We discussed this instrument, when you first acquired it. Was the maker identified? I cannot find the original thread.

Klaus

[bort]

From a post long ago...

What make?? what key? any history? any more pics?? thanks.................BB

viewtopic.php?f=2&t=41617
B.A.R.T. is a Kaiser bore WWI era German tuba currently in CC. The maker L. Mitsching and the location lberfeld (currently a subdivision of Wuppertal, Germany) is engraved on the bell.
19.5" upright bell, 40" tall, 4 rotor valves of .827" bore, and clockwork springs complement this beast of an instrument. It is surprisingly lightweight for its size due to being entirely handmade of sheet brass; the triangle seams are clearly visible on the inside of the bell.

(Overhead spot lighting in that picture really threw off the colors on about the top third of it; the tuba was not affected.)

[Frank Ortega]

Could this be the "uncut" version of Bart?

http://www.ebay.com/itm/vintage-1800s-G ... 0798492762" target="_blank

The taper looks awfully similar if you look at the shot of the Back of the horn.

Frank "has too many tubas already to consider adopting one more" Ortega

[MartyNeilan]

Could this be the "uncut" version of Bart?

http://www.ebay.com/itm/vintage-1800s-G ... 0798492762" target="_blank" target="_blank" target="_blank

The taper looks awfully similar if you look at the shot of the Back of the horn.

Frank "has too many tubas already to consider adopting one more" Ortega

Definitely some similarities, but the flanges, ferrules, and "keel" that I removed are very different, in addition to the very different keywork and linkages and lack of a bell wreath on Bart. Bart also does not have a nameplate soldered on the bell, but a stamped name and location of manufacture. The third and fourth valve wraps are also very different in the back. Maybe they are distant cousins, since this was probably made about 20 years before Bart (if they are right on the date.)

[MartyNeilan]

I am excited, the valves should be here tomorrow! I am going to take my time with the project and not rush things, though. The two trickiest parts will be cutting / bending the leadpipe and the dogleg connecting the pistons to what is now the fifth rotor.

This was a good player to start. If Marty's plan comes together, it will be a BAT of epic proportions! That horn is as big as it looks, too! HUGE!

The sound of this horn is great, a big fat German sound with a little more roundness than a typical Kaiser and no edginess. Low register is as powerful as the middle. It is also a very responsive instrument that does not require a massive effort to start each note, as some large bore tubas can require.
The horn played very well top to bottom, with only one glaring pitch problem - D in the staff was about 40 cents flat 1st valve. 1-3 with the first pushed in put it spot on. With a larger mouthpiece, the horn tended a little flat going into the upper register, but playing off the 9th partial instead of the 8th proved an easy alternative to lipping up the pitches. After I purchased the tuba, careful "tweaking" with a torch, hacksaw, file, and sandpaper brought the overall pitch of the horn up to 440 with any mouthpiece and fixed any overly long valve circuits, so every note was readily in tune. My overall goal now is to keep the length mouthpiece-to-tuning slide the same as before; the four small-piston valves have approximately the same length as the three oversized rotors I removed. Whatever length I shorten the leadpipe to get the right end diameter going into the pistons will be made up in the length of the slightly tapered dogleg connecting the fourth piston to the rotor.
The two biggest issues with the horn were physical - the leadpipe only came about 45 degrees around and the valveset was nearly 100 years old. The tuba was cut sometime in its life, either from a very low pitch CC or most likely a BBb of some pitch standard. A lot of the length was taken out of the leadpipe, but converting to a piston cluster will allow the leadpipe to go in at a much closer location to the player and eliminate the right angle bend at the end. I don't project a 90 degree leadpipe on this horn post-mods, but something in the 65-80 degree range which will still make the instrument much more playable.
The rotors were replated some years ago but have still seen better days. The linkage is worn almost beyond use, although enough of the heaviest Hetmans cuts down on the clatter. I am keeping the best condition valve (#4, no surprise) on the horn and will come up with some kind of hobby-shop linkage once I see exactly how the pistons are going to set.
My only concern with the final project on the horn is its size and girth - very wide horns are typically more accessible in either a rotary or top action configuration. Hopefully having to reach around the instrument will not prove too much of a challenge to my 5'7" frame. (The exact length, angle, and offset of the dogleg will hopefully minimize that). And, that the horn is not "too much tuba" for my real-world playing needs - but who says you can ever have too much tuba?

Marty,
I was looking at the picture and wondering the bell diameter.
Just how big is this big assed rotary tuba ?
I love it when somebody just goes for it.
Good luck !

The tuba barely fits in a 2165 gigbag; it has more overall girth to it than a 2165. The bell is close to 20 inches in diameter and the tuba is about 40 inches tall. This is a very large instrument, however, it is a continuous taper. Part of what makes it play well is that it does not flare too fast too soon. The bottom bow is huge, but the top bow more modest. Some 5/4-6/4 horns with top bows nearly as large as their bottom bows tend to have more issues. Also, the tuba is lightweight for its size, which helps to make it very responsive. However, it does not get brassy or edgy at all when pushed.

[MartyNeilan]

Will there be a semi-continuous update on the progress - with pictures if possible?

BartMockup.jpg

The valves came home last night. This is a picture of a rough layout of how it will fit together (my wife's hand balancing the valveset on the horn.)
I will take about 2 1/2 inches off the leadpipe to match up with the #1 piston bore, and most likely use that piece for the dogleg going from the valve cluster into the rotor. The "airway length" of the piston valveset is virtually identical to the 3 Kaiser rotors I removed, so I don't anticipate any significant change in pitch.
I may have to change the rotation of the now-fifth-valve to prevent any linkage issues.

[Frank Ortega]

Marty,

I think the idea of using the 4th valve as the 5th rotar is ingenious. How does the port coming out of the Piston set line up with the old rotar port? Is it nearly a straight shot? I can't wait to hear about the results. I played this horn when I was at Dillon's and loved it. I believe that Dave Grego was a former owner who may know more about the cutting.

I may steal this valve set up idea for one of my other crazy projects!

Good luck!
Frank

[MartyNeilan]

Marty,

I think the idea of using the 4th valve as the 5th rotar is ingenious. How does the port coming out of the Piston set line up with the old rotar port? Is it nearly a straight shot?

The 4th valve is a .787 and the 5th is around .827 The "dogleg" will be around 2.5 inches long, maybe longer depending on what I do with the leadpipe. I will either use the last piece of the leadpipe that is already tapered just about perfectly, OR I may just bend some straight .827 pipe and put it over the stub coming out of the fourth piston (just fits) and into the ferrule on the rotor. With the direction of the airflow, it will be no different than coming out of a tuning slide.
Undecided, I may try both and see which works better.