Re: Re: Re: 186 BBb vs CC centering/agility


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Posted by Klaus on May 28, 2002 at 17:56:30:

In Reply to: Re: Re: 186 BBb vs CC centering/agility posted by Graham Smith on May 28, 2002 at 17:07:13:

As far as I remember, I assumed the tuba discussed back ten to be a piston one. The costs of rebuilding old pistons hardly would be defendable, if the tubas was not a good one.

I am not into rotary tubas and even less into Miraphone. But that is a personal thing. Your Mira has has served you well, so a rebuilding might be worth considering.

From new well built rotors do not touch the wall of their casings. Their only touchpoints are where the axis ends are seated in the top and bottom caps. If these seat have not been distorted by violence or excessive wear, the rotors should have kept their original shapes but for a layer of surface corrosion.

They might still leak water through the test, but that would be a matter of wear between the axis ends and their seats.

By a process, that I guess is called swedging (not in the dictionary), the contact between axis and seat can be re-established. So much that some honing will be needed to recreate a free movement of the rotor. This process is only to be trusted to the very best repairmen. from what the board wisdom says, Lee Stofer would be one of those.

If this type of repair is called for, I would also replace the S-linkages with something of the ball and socket type. And maybe mount a thicker axle for the paddles. With the right fitting you should then have an instrument with the functionality of a new one.

But again the costs of these repairs can only be defended, if the tubing of your tuba has been well kept (a few loose solderings do not count as problems in this context).

Klaus


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