A Wurlitzer CX held six rolls with its automatic roll changing device.
Each roll was spooled onto cardboard tube that was held in place with
a metal spool.  One end of these holding devices was held in place
with a knurled brass nut.

I made these spools for sale and still have several left in stock at
$100.00 per spool.  It takes six of these spools to fill a changer full
of music rolls.

Don Teach
Shreveport, Louisiana