After restoring several Autophones and a pedestal leg Gem roller
organ, I have noticed that the cardboard original stiffeners are
made of a different material than today's poster board.  It looks as
though there is a greater content of rag in the 100-year-old boards.
Is there a supplier out there for this type of rag cardboard?

The warped original boards can be reused in some cases by ironing
the back side with a moist flatiron.  Some of the Autophones have had
wooden stiffeners which have less warp, but are often split.  Luckily
the last Gem I did had all the original stiffeners, so a simple ironing
and reversing made the job easier.  Thanks for any information.

Brian Walter - on the banks of the frozen Mississippi.