[ Ray Fairfield wrote, "In a vacuum operated machine, won't pneumatic
 [ leather be pulled 'in' on all sides when the pneumatic operates?

In the Aeolian vacuum operated organ that I rebuilt, the pneumatics
were mostly intact and that is the way they were all folded: the ends
were folded in and the sides were folded out.  It appears that is the
way it was done at the factory.

Howard Wyman
Valrico, Florida