Re: Faster valves


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Posted by John Swensen on July 31, 2000 at 23:09:43:

In Reply to: Faster valves posted by Carl H on July 31, 2000 at 21:41:52:

If the valves are working smoothly, it is possible that they still have nice, close tolerances, and that the rotary valve oil is too viscous. You could try running some piston valve oil down the leadpipe to rinse off some of the viscous oil from the rotors.

Another possibility is that you installed the bearing back plates a little too tightly,
and this is making the valves bind a little. Tapping down on the long spindle ends to drive the plates back out a hair might work. If the plates are not in squarely they can bind, also.

If the linkages are too tight or rough, they might lead to sluggish behavior.

A third possibility is that the springs have, in fact, relaxed a bit. If this tuba has clocksprings I don't know what to do, short of putting modern-style paddles on it. If it has paddle-like keys, you might be able to wind each side of each spring one more turn,
but this might cause the old springs to break, and they will be too stiff, anyway. Winding new springs is, actually, quite easy to do, as long as they are not clocksprings, but you should be able to buy replacement springs.


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