Re John Dewey's mystery player [190925 MMDigest] -- reply by
David JOHN Dewey!  How's that for coincidence?

John, that is a Recordo expression box, one of the easier to rebuild
ones I've seen; most have the pneumatics as part of the box itself
and are rather difficult to "un-do."

I suspect this is a "Type B" or "Type C" as defined by Bob Billings.
Either one, when in a nicely rebuilt piano, provides a great range
of expression, close to the Reproducing pianos.  I have a B in a Cable
Euphona which I love.  Recordos do require a tight player unit as they
function by bleeding off vacuum instead of restricting it.

I would love to see more of your unit.  My piano is somewhat unique in
that it also retains the foot pump, leaving very little room under the
keybed for _anything_.  The motor is on one side of the case and the
pump is on the other with a two-belt pulley system running behind the
foot pump parts.  Rube Goldberg would have been happy to claim to have
designed the mechanism, but it works well.

[Later] In studying the photo, and looking at photos of my box, maybe
yours is a "Type A" box, as mine has many more adjustments on it.

Was your box already worked over?  Something seems amiss, in that the
various bellows seem to be locked into the single threaded shaft, but
they need to work some what independently of each other (yet also be
able to "add" to the shaft movement) to provide varying levels of
"leakage" to create the many playing levels of vacuum.  That is why
each pneumatic is of a different size.

David Dewey