Haddorff Piano Co. Serial Nos.

1901	996
1904	5380
1908	25000
1912	46000
1916	66500
1920	86000
1924	102500
1928	112000
1932	115900
1936	117000
1940	124000
1943	129000
1948	129800
1952	133200
1956	167003
1960	170100

It is remarkable that data on piano serial numbers has survived so well for over a century. However, some inaccuracies are inevitable. These serial numbers are to be used only as a rough guide to a piano's age. An exact date does not make a material difference to a piano assessment. To be within 2 to 5 years is accurate enough to give an informed report on a piano.