Hello Richard,  The problem you describe is caused by the internal
cylinder filler cement having sagged (from years of exposure to heat)
to the point where it is fouling the arbor shaft and thus is locked to
the cylinder.

The _only_ cure requires a tricky procedure of mounting the cylinder
in a lathe and spinning it while heat is very carefully and gradually
applied until _all_ the internal cement has reached hot enough
temperature to liquefy and then the heat source is removed and lathe
left spinning about 45 minutes or longer to centrifuge and redistribute
that cement to its original uniform coating on the interior walls of
cylinder.

Do not try hitting the axle or other method of attempting to extract
the shaft.  If you bend the arbor it will be expensive to repair and
also may require full repinning of cylinder.

I do several of these each week so I know how to do it correctly and
not cause more damage.  If you would like me to do it for you, give me
a call:

Reg Smith - Antique Music Box Restorations
tel.: 1-706-540-8976
Dahlonega, Georgia