Julius Keilwerth brass serial numbers
The general information about the history of Julius Keilwerth brass instruments is on a separate page.
There are serial number lists of Keilwerth saxophones around but there was no such thing for their brass instruments. Below you'll find a list of instruments and numbers that were traded through Ebay, Quoka and such, with information added from sites like Trompetenforum.de (where Brigantiumjazz triggered me to make this list), Trumpetherald.com, Trumpetmaster.com, Horn-u-copia and the Yorkmaster public pictures at Yahoo. There seems to be no relation whatsoever between the serial numbers of Keilwerth saxophones and their brass instrument serial numbers.
This serial number list of brass instruments now has almost 800 entries, that's maybe 2 percent of Keilwerth brass production. It shows a fairly continuous serie up to number 30658, with a few examples of every 1000. Then, after a few incidental Tonekings, new models show up, like the 2000 and 3000 series and the Student. The jump, first to the 100.xxx range, with mostly 'Student' instruments and then to the 200.xxx range with the 'De Luxe 2000' and 'Super de Luxe 2000' models could originate in other makers providing the instruments, as stated above. Here the gaps between the numbers are much larger. That's probably because they are part of a serial number list that includes the makers 'own' instruments as well as other stencils. And maybe also because these are newer and still with their original owners, so they down't show up on Ebay and other sites? Then there are incidental examples of the Modell AT and SX of which we don't know a number. La Sete and Hamilton instruments are integrated in this list, although they're not all made by Keilwerth, the La Sete instruments in the 15x.xxx range obviously come from Elkhart, Indiana, others come from Wohlrab.
Here's a graph that illustrates the development of Keilwerth serial numbers in the list below. Steady going from zero till 30.000 and then a few high scores.
For some instrument there is a more or less reliable date of purchase know. Based on these dates the graph below is made. Note that an instrument bought at a certain time may have waited in the shop for a considerable amount of time, sometimes several years. So drawing a line between the lower dots gives an approximation of the timeline of the production of Keilwerth brass, that is the first 30.000 Keilwerth instruments, which I believe is their own production.
There also are Keilwerth brass instruments without a serial number but with the valves numbered. The trumpets without a serial number mostly have an additional bow in the main tuning slide, a feature that's seen more often on pre-war trumpets. Therefore I think these are the first Keilwerth brass instruments, before the serial numbers started. Trombones also seem to be missing a serial number quite often. There are also serials in the lower range that begin with a zero. These seem to be a separate line (most Toneking model) where (most of the) the De Luxe models are without the zero.
For additions and corrections: please contact me. Information about the year your instrument was acquired is very helpful. Thanks to everyone who has contributed to this list so far!
 Serial numbers 27 - 4.999
 Serial numbers 5.000 - 9.999
 Serial numbers 10.000 - 14.999
 Serial numbers 15.000 - 335.308