Hello MMD.  I have just been down in my workshop, mulling over the
upper action from my 1919 Steck upright Duo-Art.  It is a three-decker
-- the first I've encountered since I rebuilt my Aeolian 65-note
pushup, about 25 years ago.

There is nothing remarkable about the two lower decks, but the top one
is different.  It doesn't have the usual wooden strikers, or pitmen.
The reason for that is obvious -- there isn't room!  Instead, each of
the pneumatics in this deck, incorporating every third note from 1 to
88, has a small, domed, brass knob screwed into the finger that
protrudes from its moving board.  There is nothing surprising about all
that, but why don't the brass knobs line up with the fingers from the
other two decks?  They are all about 1/8" closer to the front of the
action than are the wooden fingers.

Then, supposing that the pneumatics have all been adjusted to provide
the same vertical movement to their pitmen, won't the top deck wippens
move a little more than all the others?

John Phillips - in Hobart, Tasmania