My roll scanner is undergoing modifications to accept A, G and O rolls.
I now have samples of all three formats in my hands, but no nearby
O-roll orchestrion to verify how an O-roll flows.

My Cremona A-roll coin piano roll is driven from its left side and the
drive key is mounted inside the left side of the roll's core when
mounted in a piano.  These rolls flow from top to bottom, similar to
conventional 88-note piano rolls.

Similarly, G-rolls flow from top to bottom just like 88-note rolls,
driven from left side, with a drive key inside the left side of the
roll's core.

However, how do O-rolls flow?  From top to bottom, from bottom to top,
from the inside or from the outside?  And driven from what side when
mounted?  On what side of the core is the key mounted, when seen in an
instrument?

In Bowers' "Encyclopedia", on page 546 is a picture of a Coinola spool
box that suggests that an O-roll flows from the inside, but makes no
mention of whether it flows from the top or from the bottom.  Reblitz
(p. 362) also makes no reference how the paper flows.  Do all O-roll
instruments have their rolls flowing according to a fixed standard?

What other rolls can be mounted on a set of A-roll 3-1/2" spool ends?
And what other rolls can mounted on a set of O-roll 3" spool ends?

Regards,
Terry Smythe
Winnipeg, Manitoba, Canada
http://members.shaw.ca/smythe/rebirth.htm

 [ Some photos of representative spool frames are at
 [
 [   http://mmd.foxtail.com/Tech/SpoolF/index.html
 [   http://mmd.foxtail.com/Tech/SpoolF/coinola.html  O-roll
 [   http://mmd.foxtail.com/Tech/SpoolF/cremona.html  A-roll
 [
 [ When an "O" roll is played in a Coinola spool frame, the supply roll
 [ is at the top and the paper unwinds from the back side of the supply
 [ roll, then over the tracker bar and onto the back side of the take-up
 [ spool.  Coinola instruments equipped for playing "A" rolls use the
 [ same spool frame but the spools turn the opposite direction (i.e.,
 [ they spin as in other makes of "A" and "G" instruments).  -- Robbie