Hi John,  The Stems Grandiola that I restored was fitted with an early
Autopiano player mechanism.  Research indicated that in approximately
1910-15 a deal was struck between Stems and Autopiano, New York, to
supply player actions.  I do not believe that the Stems firm ever
manufactured their own player mechanism, but retro-fitted the systems
into their beautifully built pianos.  It was an exceptionally easy
full restore.

Unfortunately, due to the total destruction of Dresden during the WW2
firestorm, all records of the company were lost.  The Autopiano player
installed was indeed deluxe in materials and workmanship, but had only
Themodist style expression.  Could the 5 inlets at either end of the
scale be a Recordo style?

This Grandiola is the only example I have ever encountered of this
make, but I do believe that Hupfeld definitely provided their player
mechanisms to the Stems company at some point in their history.

I am sorry that I cannot provide further information.

Paul Brennan

P.S.: You will find that the piano action also was built by another
German company.  That led me to believe that the cabinets and possibly
the plate were the only items that Stems actually produced themselves.