Kevin Pfeiffer asks about a tool to aid in removing the lost motion
between stack and piano action. My Mason & Hamlin upright has the
piano stack sitting above the keys with standard capstans at the end
of the pneumatic fingers.
I puzzled over the same issue until I made an adjusting tool from a
length of coat hanger wire, about 12 inches long: a small open triangle
on the bottom that would enter the holes in the capstan and slide
between the pneumatic fingers; the other end was bent 90 degrees so
I had some purchase when turning the capstan with the inserted small
triangle wire. Putting just a 90-degree bend on the small end makes
the adjustment more difficult, as the turning point center is offset
from the capstan.
I would put the stack in the final position and run the wire down
between the pneumatic fingers, turn it 90 degrees and pull up, gently,
on the finger. That would give me an approximate idea of how much lost
motion I needed to remove. I would then slide the stack out just a
little, until I could get to the capstan, insert the triangle in the
capstan hole and turn it however much it needed. Then push the stack
back to final position and check lost motion again.
After doing three or four capstans you will get an idea as to how much
to turn each capstan. It saves having to lift the stack out every time
and there is usually enough slop in the forward movement of the stack
(for removal) to allow the minimal movement of the stack in this
Maybe other readers have another idea?