Hi everyone,  I am new to the MMD and my main interest is large
mechanical organs, but I do have an interest in all mechanical
instruments.  The correspondence on the Pistonola has prompted
the following as my first contribution.

A few months ago I found five books, (one from the 1900's and four
from the 1920's) on player pianos on a second hand book stall on a
market at Southwell near where I live (Mansfield England).  One of
these from the 1920's, by D. Miller Wilson, is called "The Player Piano
-- Its construction, How to play, What to play and how to preserve it
and make adjustments when necessary."

There is a chapter on makers, and by coincidence I was reading the
entry for the Pistonola earlier this week.  I am not sure if it is too
long for inclusion in the Digest, but here goes.  It has been carefully
checked against the book.

Keith Pritchett
Mansfield, England

 [ Welcome to MMD, Keith, and thanks very much for this timely article.
 [ This is the first account of the Pistonola we've seen written in the
 [ heyday of the pianola.  See the images supplied by David Evans at
 [ http://mmd.foxtail.com/Pictures  -- Robbie

 - - -

  "The Player Piano -- Its construction, How to play, What to play
     and how to preserve it and make adjustments when necessary."
                       by D. Miller Wilson

The Pistonola.  This instrument is manufactured by Boyd Ltd., London.
The action is all metal and works with a tension twenty-five times
greater than that usually employed in pneumatic players.  The action
can be installed into a piano of ordinary dimensions.

Instead of bellows, self lubricating pistons are used, fitted in a
single row of metal cylinders.  The pistons are made of a special
composition of graphite, compressed and moulded with a glass-like
surface, and work silently.  The air chambers are so small that a
metal block 4.75 inches by 1.5 inches contains nine complete striking
pneumatics.

The device for accenting melody notes is called the modulist, and is
controlled from marginal perforations in the music roll.  There is
also a device called the crescodant by means of which crescendos and
diminuendos are obtained.  The following explains the modus operandi of
the pistonola action.

When a perforation in the music roll opens the duct in tracker bar,
air passes down the tracker tube and up under the plunger situated in
the front part of valve block, the air then lifts plunger, this in turn
lifts small cone valve (called primary) off its seating, the air then
passes down by the stem of the valve at the back of valve block;  this
valve consisting of washer discs, plunger and ball is called the
secondary valve.

The air lifts ball off its seating by means of washer and plunger up to
top of seat, thereby shutting of ball chamber from the atmosphere;
this chamber is in communication with the cylinder by means of a hole
in the side, another hole leading from this at right angles direct into
cylinder, the air space above the piston in cylinder is now in direct
communication with the main air supply by means of opening under ball
seat, the air in space above piston is now drawn out by suction of the
pumps, causing the atmosphere on the outside to push the piston up,
lifting the whippen by the connecting cord.

Normally the air in space above piston is in communication by means of
the seat opening above ball.  While a note is being played there is a
partial vacuum above the piston, but as soon as a hole in the tracker
bar is shut off by the music roll the valve falls back and the air from
the atmosphere passes back through top seat, opening the ball chamber
and then into cylinder, the piston then falls into normal position.