Hello,  On the following page one can find serial numbers for Steck:

  http://frontpage.sofnet.com/kway/serialnumb.htm

The number of pianos produced is irregular, but the list shows an
average of 2000 pianos a year except for 1930 (the year mine was made).
Here the number is ... 36000 (from serial number 85000 to 121000) ?!?
After that it returns to an average production of 2000 pieces.

What happened that specific year, 1930?  I believe it's because the
Depression sales went down.  Based on the serial number they seemed to
have boomed.  Or was the numbering-system changed that year?  Can
anyone shed some light on this mystery ?

Regards,

Patrick Boeckstijns