John Tuttle asked about estimating the date a piano was manufactured.
You would have to know the starting number and finishing number per
given day.  The answer to this question would differ greatly among
piano makers.

According to an elderly gentleman who worked for Foster & Co., the old
East Rochester combined companies were capable of anywhere from 60 to
75 pianos a day, including the output of the Marshall & Wendell company
of New Albany.

The combined companies did not make many components: the actions
were from Pratt-Read & Co., the key-frame and keys were from a company
in Binghamton and, of course, the player actions came from Standard
Pneumatic Action company in New York City.  The above components came
made-to-order and ready to install.  Pianos could be made in great
numbers by having the parts arrive all ready to install.

The American Piano Company cast their own plates, brackets, pedals
and casters at East Rochester Iron Works.  Upright strung backs were
built in what the old man referred to a "large round building" that
used to stand on the site.  Serial numbers were not assigned to the
strung backs at this time.  The identical strung backs were distributed
to the subsidiary companies on-site, and some were shipped by train to
Marshall & Wendell in New Albany.

Once the subsidiaries received the strung backs, the nameplates were
added and the piano case was installed.  The pre-made piano actions and
keybeds were installed and regulated.  Before the player actions were
added, a serial number was assigned and painted on the plate and
stamped in the back.  The subsidiaries were nothing more than
assemblers and case makers.

Although the pianos were almost identical, at least internally, the
serial number could not be added until it was ascertained which brand
name would bear.  Most of the different brands had a different
numbering sequence, except for Foster & Co., upright Stoddards and
Armstrong, which shared serial numbers.

Even though the serial number in an old piano is seen through a small
"window", that doesn't mean that it was stamped before the plate was
installed.  If you look closely, you will never find any part of the
numbers behind the plate.  I maintain that the numbers were stamped
after the plate was installed at some point, probably toward the end of
the line, as per pianos completed, and not always in strict sequence.

Andy Taylor
Chief Arranger
Tempola Music Rolls Inc.