Re: Re: Re: St. Pete "German Machine"


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Posted by Rick Denney on August 30, 2000 at 11:24:45:

In Reply to: Re: Re: St. Pete "German Machine" posted by George on August 30, 2000 at 09:48:50:

I'll answer that, too, and hope I don't step on Jay's toes in the process.

I believe that Jay was referring to the linkages only, and not to the touch-pieces, springs, and frame. Those add considerable cost, as you know. But I wonder how many times those are replace unnecessarily when it's just the linkages that are in trouble.

For the linkages, the parts include control-rod ends designed for radio-controlled model helicopters. The ball is a brass ball with a 4-40 bolt running through it, and the socket is a plastic, adjustible socket that threads onto 4-40 threaded rod.

I remove the old linkage, which requires grinding off the peened end of one of the pins. I remove the pins (on a Miraphone they are threaded in place). On a Cerveny, I had to grind the pins off and drill (by hand) new holes in the touch-piece lever arms. I bolt a brass ball onto the touchpiece using a 4-40 bolt and nut.

I remove the old linkage from the stop arm. For old S linkages, the S-arm fits into a clevis in the stop arm, with a pin or screw securing it in place. With old ball-and-socket linkages, the stop arm will have a ball threaded in place. Remove it, or the pin. I bolt a new ball to the front of the stop arm using the existing hole. This sometimes requires drilling and tapping a larger hole. I usually drill a smooth hole, and fit a nut into the old clevis notch, and thread the bolt in from the front of the horn.

To make the linkage, I cut 4-40 threaded rod to the right length (determined by trial) and thread the sockets to either end. Then, I usually have to carve away a bit of the socket to get it to clear the stop arm on all the valves. On one occasion, I bend the linkage to provide clearance, but don't do that until the next step.

I then remove the socket from one end and slip a 1/8" ID brass tube over the 4-40 rod to make it look good, and reassemble. The sockets I use have tension screws that must then be installed, and generally left loose. A couple of spots of light oil, and I'm done. The action will be just the tiniest bit sluggish for about a week until it breaks in.

I've done this procedure on a Miraphone 186 BBb (replacing a worn-out DVS linkage), a 186 CC (replacing S linkages), a Sanders/Cerveny BBb (replacing the cheesy light-weight Sanders ball-and-socket linkages), a Musica F (which used clock-springs on the touch-pieces) and a Rudy Meinl BBb.

And, yes, the parts cost about $20.

My Miraphone has these linkages, and you can see it at the link below, though it ain't what I'd call a close-up. Look down the page. You can at least tell that it doesn't look overtly ugly from five feet away. If there's demand, I'll take and post a closeup.

Rick "Tuba playing and tinkering go hand in hand" Denney



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