Rebuilding Valves
By Larry Fisher
> leathers from the Player Piano Co.!! They're too thick. Don't use the
> neoprene sponge rubber-faced secondaries they sell either - they showed signs
> of hardening and loosing their sponginess already and would not seat right,
I've not had that problem with a slightly different thickness in the leather. The whole assembly needs to be re-calibrated anyway, including valve travel, so a one more difference in thickness never was an issue. Finding a cow with the right thickness of hide that is consistent about it would make for an interresting afternoon. I've tried making them stupid punchings myself and decided that my time was worth the $35 or so dollars to have them made so nicely by someone else. To each his/her own however.
Good to hear about the sponginess of the foam. I'll watch for that. Once again, I've not had that problem here. The foam you speak of is black?? Glued to a fairly thick metal disk? Like that of a washer? We're talking the exhaust end of the valve right? Or are we talking the smaller diameter, thinner, white, spongy stuff?
> He's going to convert it into a single valved
> system with a few bypass holes drilled here, a few bleed cups there, etc.. It
> makes sense, since we're now going to directly remove a whole set of
> problems; the reduced amplification will be negligable, sez builder. He's
> done these things before with "trouble" units with success, contending that
> they played even better than original (presumably due to the reduced
> mechanical chain of events that now has to occur to play a note). Has anyone
> else had any experience with this type of operation? Am I being a hack by not
> investing the $$ and time to strip the thing down totally and starting again
> <BIG-time sob>? Why did the good folks at Autopiano do a double valved system
> when the technology existed in 1917 for signle valves (didn't Standard,
> et.al.)? I realize it was in the name of amplification, but were they just
> trying to build in some additional protection by overamplifying the tracker's
> signal?
As I understand it Karl, the two valve system was so that after the piano had been moved, (all the valves being in limbo, neither on, nor off and it took furious amounts of pumping to get all the valves back into their either or position) it could be played with a minimal amount of effort.
I've not really seen or tried to eliminate the upper stack of valves, but I've read where this is possible and sensible. Adjusting the little beggers is quite easy when compared to the larger valves down below. After re-pouching, re-leathering, and re-shellacing everthing, I re-glue the top valve (exhaust) on the wood dowel with PVC-E glue putting a .010 shim betwixt the leather and the valve seat. This .010 stock is available at every hobby store in this area anyway, it's brass about 3/8" wide and about 6 to 8" long. I cut a notch in it to accomodate the valve stem dowel. This sets all the valves at the same travel and I've never had a problem with it.
Autopiano made a nice player. Good luck and thanks for the info.
--- Larry Fisher RPT, Portland Metro's Authority on PianoDisc Systems
For more information call (360) 256-2999 in Vancouver, Wa.
or email larryf@pacifier.com |
(Message sent Wed 18 Oct 1995, 12:59:51 GMT, from time zone GMT-0700.) |
|
|
Mechanical
Music Digest™ Archives
