druby wrote:My concern on a Tuba is that you have to move a much larger slide a longer distance to get the same effect. It has to have a very quick release and return (ergo strong spring mechansim) and the fit, finish and alignmnt on the slide has to b perfect for this to all work. Sounds like an accident waiting to happen to me (given that Tubas are more dent/ding prone than most other brass instruments).
These issues have been worked out one at a time in many cases.
I built a spring-loaded tuning stick for my Sanders Bb tuba (a Cerveny). It had a bell crank to operate the sideways slide using a T-handle at the top. It flattened the instrument when you pushed it down, and then returned to a normal set position. That slide was surely not perfect, but it worked. It was inspired by a (better made) mechanism of similar design on a 188 owned by Jay Rozen.
On a Vespro, the fifth partial was unusably flat. I built a tuning stick for the sideways main slide that sharpened the instrument when pushed down. I mounted it alongside the first valve slide and put a thumb ring on it so that I could sharpen the main slide using the left hand while it was resting on the first valve slide. My tech and I adjusted the main slide to work appropriately fast. It still wasn't perfect by Blokian standards but it worked.
My plastic Martin tuba has a tuning stick which is just attached to the side of the downward-pointing main slide. That tuning stick was installed by or at the request of Lenny Jung, its previous owner. I suspect its main purpose was to overcome the valve swindle since the instrument has only three valves.
Speaking of valve swindle, Don Stauffer, who first coined that term, recalls receiving a conductor complaint concerning the tuning of the third partial on his Conn BAT back in the day. He describes installing a curtain rod as a tuning stick on that instrument, in the 1940's, and how its success led to similar devices on his later tubas. In fact, it wouldn't surprise me if he and Lenny Jung had compared notes on the subject.
The Martin and Vespro were not spring loaded, and on reflection I see no need for spring loading. We manipulate the first valve slide all the time with no spring-loaded resting place.
All of these mechanisms were suffiently inboard to prevent damage from minor accidents, and provide at least two inches of slide movement. The ones I build (and the one of the Martin) were pretty primitive mechanically. In the ones that I built, I didn't do any soldering at all, but attached the mechanisms to the instruments using nylon wire ties.
Rick "thinking it would be easy for the manufacturers to provide main-slide tuners" Denney
