[ Ref. "Humidity Control in the Desert, or Anywhere"

Hi all,  early in my association with player pianos I found that
varying humidity was a problem, and as a mechanical engineer I work
on solutions.  First I noted that gaskets, especially new cork ones,
would develop leaks and I solved this by using Belleville spring
washers under the screws to keep the joint of the gasket to wood or
other surface leak free.

Since the Belleville washers take up part of the screw or bolt length,
I some times needed a longer screw and to save money adjusted the depth
to which the screws cut into the wood by sometimes including one or
more plain washers.

The Belleville washers are made of spring steel and are dished so as you
tighten the screw the Belleville washer flattens; if the wood shrinks
the Belleville washers cup slightly thereby maintaining the compression
on the joint.

The Belleville washers are very helpful in keeping the 1922 to 1924 or
so Ampico "A" stacks air tight when they are held up in the piano via
bolts and have new cork gaskets between the decks.  The same is true
for all the little valve assemblies like the Deluxe tracker, the Deluxe
rewind/replay, etc.

In regard to my earlier post on humidity control I should also add
that here in the Maryland area, when the temperature drops to zero or
to 15 degrees F. I must back the humidity down in the house or I will
get condensation on the windows and on the wall behind the china
closet.  I have even seen ice form on the double-pane windows.  When
you expect or experience this condition it is wise to lower the
humidity in the house to avoid these problems.

Allen E. Ford