Hi,  It is possible that Al Meekins might be able to help.  He is a
first-class musical box restorer and has a fully equipped machine shop.
He can certainly supply Polyphon mainsprings.  I doubt if he subscribes
to MMDigest but John can email him on ameek37754@aol.com.geentroep
[delete ".geentroep" to reply].

Regards,

David Evans
Vancouver Island, British Columbia, Canada