I am in the process of rebuilding my Schiller player piano.  According
to Art Reblitz's book, the action is a Standard action, my clue being
the "S" symbol on the pump pedals.

In restoring/recovering the pneumatics,  I do not understand the
purpose, usage and adjustment of very small flanged screws in the top
board (fingerboard) of each pneumatic.  Opposite the path of the screw
is a felt pad glued into a round hole in the lower pneumatic board.

Some of the pneumatic screws were barely into the fingerboard, while
others were almost totally screwed into it.  Obviously some sort of
adjusting screw.

I looked through the MMD Archives trying to find previous articles on
this subject, but found none.  If I missed it, please point me to the
article.  If not, can someone advise me as to the full purpose, why and
when to make adjustments of the screws?

Logic says it would have something to do with keeping the pneumatic
from closing too much, or making them all have the same closing depth.
Is this on the right track?  Would these have any part in adjusting the
valves?  Were these used to adjust the pneumatic as the action went
through normal wear from usage over the years?  Any help for an old
musician?

Just havin' fun and tryin' to do it right.

Bob Barlow
Bartlett, TN