I'm posting the latest update to my Gustav Becker serial number dating tables here for info. Please refer to the notes and also the the logos earlier in this thread for proper use of the tables. These tables were originally posted November 19, 2006.
September 7, 2014:
NOTE TO ALL: NEW information has been confirmed regarding when GB was taken over by Junghans (May 1930) that has changed the summaries posted after the serial number tables. Also, both Freiburg and Braunau numbers have changed modestly in the years 1918 to 1925 as a result of the transition from the traditional GB numbering to a new system, implemented mid-1925. These tables have been updated as of this date. You can use the tables with confidence that your clocks can be accurately dated.
PLEASE NOTE THESE ARE COPYRIGHTED BY JOHN HUBBY ©2003-2020 BUT MAY BE USED FOR PERSONAL INFORMATION. PLEASE REFER TO LOGO TABLES FOUND ON THE FIRST PAGE OF THIS THREAD TO ENSURE YOU ARE COMPARING APPLES TO APPLES!! An update of the logo tables is in progress and will be posted later this month.
Just a note of caution on GB serial numbers. Kochmann's data is reasonable up to 1900 but had to be adjusted to ensure accuracy based on latest info per table below. After 1900 his data is seriously wrong. Also, they apply only to the Freiburg works. The Freiburg works produced about 2,510,000 serially numbered clocks from the beginning in 1847 up to mid-1925 when the numbering system was changed for as yet unknown reasons. Here are Freiburg works serial numbers for the period 1847 through mid-1925, taken from a table I have developed from a database of over 3,500 clocks including many dated examples in that period as well as being dated by patents, trade advertisements, catalogs, and other information.
1847: 0000001 1848: 0000051 1849: 0000121
1850: 0000251 1851: 0000481 1852: 0000721 1853: 0000971 1854: 0001241
1855: 0001541 1856: 0001881 1857: 0002271 1858: 0002721 1859: 0003251
1860: 0003901 1861: 0005101 1862: 0006901 1863: 0009301 1864: 0011901
1865: 0014801 1866: 0018001 1867: 0021701 1868: 0025901 1869: 0030601
1870: 0035801 1871: 0041801 1872: 0049501 1873: 0059901 1874: 0073001
1875: 0089301 1876: 0109001 1877: 0132401 1878: 0159901 1879: 0192001
1880: 0228701 1881: 0270001 1882: 0316001 1883: 0365001 1884: 0416001
1885: 0469001 1886: 0526001 1887: 0588001 1888: 0656001 1889: 0729001
1890: 0805001 1891: 0882001 1892: 0958001 1893: 1030001 1894: 1096001
1895: 1156001 1896: 1212001 1897: 1265001 1898: 1316001 1899: 1366001
1900: 1441001 1901: 1530001 1902: 1610001 1903: 1683001 1904: 1753001
1905: 1821001 1906: 1887001 1907: 1951001 1908: 2013001 1909: 2073001
1910: 2130001 1911: 2184001 1912: 2231501 1913: 2266001 1914: 2285001
1915: 2297001 1916: 2306001 1917: 2315001 1918: 2331001 1919: 2349001
1920: 2370001 1921: 2393001 1922: 2418001 1923: 2444001 1924: 2470001
1925: 2496001 1925.5: 2510001
These numbers indicate the first serial number used for each calendar year. Highest recorded serial number to date is 2508167. The numbers highlighted in BLUE have been changed as a result of the new information noted above.
In about May 1925 GB stopped using their traditional consecutive serial numbering system that included all types of clocks except for their pendulum alarm clocks (1876-1914). They also ceased using the circular GB anchor logo and the Medaille d'Or at the same time. Only the GB anchor logo or Gustav Becker name is found on clocks made after the change. It isn't known why this was done, however GB had just completed the 25th anniversary of the 1899 Vereinigte Freiburger Uhrenfabriken (VFU) merger and it could be the seven-digit numbers were becoming cumbersom. The new serial numbering system started with the number "1", but this was used simultaneously for at least four different types of clocks. Thus we find a multiple number of clocks of different types with duplicated serial numbers. This new system was applied to 400-Day clocks, spring driven Westminster mantel and wall clocks, some hall clocks, and weight driven wall clocks. The following serial numbers apply ONLY to 400-Day clocks and spring driven Westminster mantel and wall clocks made at the Freiburg factory from 1925.45 through 1932 when the factory was closed:
1925.45: 0001
1926: 0566
1927: 1451
1928: 2201
1929: 2851
1930: 3471
1931: 4071
1932: 4661 to 5000
All date and number information here is new at this date except the beginning and projected ending serial numbers. Here again the numbers shown are the first serial number for that year. The highest serial number for 400-Day clocks recorded to date is 4990; for Westminster clocks 4797.
Now here is the one that causes the most confusion regarding GB serial number dating. The GB Braunau (Bohemia) works was in operation from February 1888 until May 1930 under Gustav Becker when GB was taken over by Junghans. Braunau had their own series of serial numbers that started with "1" in 1888 and ended about 922,000 at mid-1925, the same time the change was made for Freiburg clocks. What happened after mid-1925 is explained after the chart.
If you have a GB clock with the two "traditional" logos (Gustav Becker Freiburg i Schl and the "Medaille d'Or"), that clock will have been made in the Freiburg works. HOWEVER, if the logo has the following: "Gustav Becker Freibug i Schl. Braunau i Boehm", plus the "Medaille d'Or", THAT clock was made in the Braunau works and its serial number does NOT correlate with Kochmann's data. In fact, he says in "The Gustav Becker Story' that there is no data available from the Braunau works.
I have developed data for the Braunau works using the same methods that were used for my Freiburg research, and the following applies to the Braunau clocks, based on nearly 700 actual examples at this date:
1888: 000001 1889: 015001
1890: 031501 1891: 049001 1892: 067101 1893: 085701 1894: 104801
1895: 124401 1896: 144601 1897: 165501 1898: 187101 1899: 209601
1900: 233001 1901: 257401 1902: 282801 1903: 309101 1904: 336201
1905: 364001 1906: 392501 1907: 421701 1908: 451601 1909: 482301
1910: 514001 1911: 546801 1912: 581501 1913: 618901 1914: 657501
1915: 696101 1916: 732601 1917: 766001 1918: 794001 1919: 819001
1920: 841501 1921: 861501 1922: 879001 1923: 894001 1924: 906501
1925: 916501 1925.5: 922001
These numbers indicate the first serial number used for each calendar year. Highest recorded serial number to date is 921794, the 1926 first number is an estimate. The numbers in BLUE were changed following the discovery of the earlier mid-1925 transition date from the traditional GB serial numbering system to the new system.
Braunau also finished some clocks after mid-1925 using the new numbering system; however we do not have enough data to provide an estimate of total made under this system. The highest such number recorded so far is 627. It appears that from 1926 until the Freiburg factory was closed at the end of 1932, the Braunau factory was used to assemble non-serial numbered clocks for GB. Sometime after the Junghans takeover in May 1930 the factory started assembling Junghans clocks, which continued up to the beginning of WWII.
Please understand this Braunau data is still a work in progress and subject to change. I think it is quite good from 1888 through 1913, because there are significant technical differences in the clocks of this period from the later ones. In 1913 Branau started finishing a special grade of GB's "Amerikaner" movements and stamped them with a Braunau serial number. This was done to the beginning of WWI and stopped until the war was over since the Freiburg factory had been converted to make war goods and all the Amerikaner movements were evidently made at that factory. From the time of the Armistice these movements were stamped "Made in Tschechoslovakia" in addition to having a Braunau serial number, which was continued up to mid-1925.
When using any of this data, first thing to do is check the LOGOS. One other check is to see if the clock has coil gongs or rod gongs. If it has rod gongs it cannot have been made before the end of 1898, as that was when the German patent was issued to Johann Obergfell for the invention of rod gongs. In 99% of the cases, if you find a GB clock with a low serial number and rod gongs, it will have been made in the Braunau works and thus quite a number of years newer than would be indicated by Kochmann's data. This will cause some heartburn for some collectors, but as they say those are the facts.
To help develop this info further, I will very much appreciate being contacted off list with info from your clocks . . photos of back plates are essential, also full front view. I'll try to help you date your clock based on that info. In particular, I am interested in receiving ANY info from clocks that have dated presentation plaques or inscriptions.
John Hubby