Installing player action in old upright piano appears to be a job of
"nightmare" proportions.  The piano virtually has to be taken apart
and then care taken to get everything perfectly in line.  The tone
may be altered as well.

I made a player action for a non-player console and, unknown at the
time, started my own nightmare.

I drilled the key bed for each of the 88 notes for the push rods.
Two aluminum racks were made each to hold 44 pistons.  Many holes were
drilled in the racks for centering the cylinders and securing them.
They were off-set to achieve the correct spacing, so some push rods
were straight, others offset.

The cylinders were 1-1/2" brass.  The pistons and cylinder head were
made of Delrin (a combination of Teflon and Nylon) with just a "good
fit" for the pistons and grooves made for "O" rings and rod seal, etc.

When machining the Delrin, the last few tool cuts have to be done very
easy, otherwise the material heats up and will shrink on cooling,
giving too much clearance.   The brass tubing is very difficult to cut
accurately without damage.  Not forgetting in all this, there are 88
of them to make!

All the pistons have to be individually installed on the racks, under
the keybed.  If I was making another unit today, this would not be so.
The system operates on around 20 inches H2O vacuum.  The piano, having
little depth, has the roll frame hung under the keybed with the
governor and wind motor behind, all with their respective linkages
to be made.

The second piano I purchased was a "genuine" player!

See some photos on the MMD web site at
http://mmd.foxtail.com/Gallery/Pictures/bentleyPiston.html

Steve Bentley
Vancouver, British Columbia, Canada