Interesting, as my first player piano (a fine upright, Leckerling
Bros.) was found in a school, sans stack. I repaired a piano purchased
from a home that literally had a hole in the floor of their living room
(a cave in, not on purpose) and traded the Leckerling; kind of a shame
that they got that particular piano, as it had a beautiful golden
quarter-cut oak case.
I then found an orphan stack and adapted it into the piano. I still
have it, and still plays, even though I've only recovered the roll
motor. The motor speed regulator isn't quite right, but we've enjoyed
this piano for over 27 years now! I'd better go back and get that
piano -- good tone is a lot harder to find than adaptable player parts!
PS: Now we've got a Welte baby grand to rebuild, and I don't think
anyone has ever tinkered with it!