Lachenal (approximate) dates of manufacture
From: "Guido Bos"
 Formulas for Concertinas
Date: Mon Jan 19 17:02:32 EST 1998
Organization: UUNET Benelux
My dear friends,
I was very surprised to see some of you trying to use the
formula for calculating the age of an English or an
Anglo system. It ends up somewhere in the year 2000.
Therefore, here are the formulas that can be used to
calculate approximately the age of your instrument
for each system.
For the English system: (serial# / 769) + 1850
For the Anglo system: (serial# / 4176) + 1850
For the Duet system: (serial# / 111 ) + 1873
This is a bit of guess work! However, it will give you
something to do when you are not practising your music.
Maybe a helpfull item to add to the FAQ Chris ?