I am currently working on a late Mason & Hamlin Ampico B.  All
is going well with the project and it looks to be a fine example.
However, when I was disassembling the stack I noted that on a previous
rebuilt someone had adjusted the stops on all five of the lost motion
compensator pneumatics so that there was no travel at all.

I have started trying to adjust this feature to working on my bench,
but I am finding that the suction required to lift the poppet wires
is very high (40+").

I noticed that there are five flat springs which reside on top of the
arms that the guide rail is hinged on, and two (the end ones) are
applying downward pressure, and the other three are applying upward
pressure.  Are these springs suppose to act as a "counter weight", so
that the amount of force required to move the guide rail is lowered?

I have gone through the "Ampico 1929 Service Manual", and "Rebuilding
The Ampico B", and found that very little is said about the proper
adjustment of this mechanism.  I did note that the lift for the hammer
rail is suppose to be about 7/8" (according to the 1929 service
manual), and as a starting point I went for 3/4" travel.  This seems
to be a very long travel.  Is this correct?

I am hoping that someone will have some more information about this.
Searching the 'Net has revealed no help.

Thank you in advance

Ed Copeland
http://www.ourmusicalhouse.com/

 [ I believe Dr. Hickman wrote in one of his papers that the hammer
 [ rest rail, when pushed toward the strings, should reduce the hammer
 [ travel distance to one-half normal distance.  This definition is
 [ not as specific as in the 1929 Service Manual (written primarily
 [ for pianos made by American Piano Co.).  -- Robbie