Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Why The 621 is so expensive?


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Posted by Rick Denney on January 29, 2001 at 11:43:49:

In Reply to: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Why The 621 is so expensive? posted by Chuck Jackson on January 26, 2001 at 21:59:47:

Chuck, you might find it easier to have new hollow rotors made. The older Cerveny instruments--even the cheapie stencils--had hollow rotors that were really fast. I had one that was made in about 1980 or so, and those valves were less than half the weight of a solid rotor as in my Miraphone.

I would think a craftsman could make a paper pattern by wrapping the solid example with paper and tracing the edges. He could transfer this pattern to a sheet of brass, cut it out with a fret saw (or something with built-in horsepower), and then roll it to achieve the desired shape. Then, he would braze-weld or silver-solder the edge, mount it on a round mandrel, and machine it to make it perfect. The knuckles connecting the ports would be made the same way as they are in piston valves, and soldered to the shell. I'd probably put a flat plate connecting the two sides of the rotor, between the two knuckles, to provide compressive strength through the valve so that it won't distort when you tap it out of the valve casing for cleaning. Then, a flat plate on the top and bottom with shafts machined and soldered into place. This is a lot of work, but not seemingly that much harder than the miracles I see these guys do with old horns. How much would it cost? Could one of you gurus do the work in four hours per valve? That would cost $1000 for a five-valve horn, but the rotors would have replaceable shafts and would last forever, and they would be lighter than a piston valve.

Rick "is that all that much worse than skeletonizing a solid rotor?" Denney


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