I got this message and thought that this might be of general interest :

> Von:          Damon E Atchison [SMTP:damon66@juno.com]
> Gesendet am:  Donnerstag, 15. Mai 1997 03:50
> An:           Robert.Hopp@quercus-hopp.com
> Betreff:      the book mechanical music device.
>
> Hello, I am an owner of a '21 Beckwith player piano and I'd like (and
> have already) started to build a small orchestration.  It will have 30
> notes and I'll need to run it off books.  I don't know anything  about
> how books work as opposed to rolls.  How does it get read, and how
> does it transfer the air signal to the valve etc.
>
> I know how valves and vacuum systems work.  I know how all player
> pianos and other things work *completely*, I am just confused on the
> roll devices.  I have found NO books on them.
>
> If you could send me some drawings via a scan please send them to me
> at: Damon66@aol.com, and tell me you sent them at: Damon66@juno.com,
> as I don't regularly check my AOL mail for anything important.  I
> would *sincerely* appreciate any help on this you could give me.
>
> Damon Atchison
> Damon66@juno.com

Actually I have no drawings to send you but I can tell you how book-
reading devices work.  There are 2 systems : mechanical and pneumatic.

Mechanical is with steel keys in the right division falling in the
perforations, pushed by springs from the underside, opening valves with
that movement, directly to pipes in small organs or to pneumatic relays
in bigger instruments.  These devices need thick (0.6 mm up to 1 mm) and
varnished books to resist damage from the keys.

Pneumatic systems with books work rather the same way as paper roll
devices.  The only difference is in driving the book : if in one case you
drive the spool to move the paper, in the other case you drive the book
directly.  It is thick enough to pass through rubber-coated rolls without
deformation.  Here the books used can be much thinner, from 0.3 mm to 0.6
mm.  The pneumatic systems are about the same.  I would avoid vacuum
systems because they don't clean themselves as pressure systems do, and
with books you will have more dust than with rolls.

Robert Hopp