[ Don Barton wrote in 050813 MMDigest:

> In response to Bruce Mercer's inquiry about the piston airmotor
> [050812 MMDigest], his is from a 4-tier Gulbransen action.

No, It's definitely not from a Gulbransen.  I have that [Gulbransen]
action and airmotor you are referring to in a Mueller-Haines piano;
it has pistons instead of slide valves but it does have teeter/totter
pneumatics.

The motor in question has no conventional pneumatics at all -- no
movable boards.

Bruce Mercer