BAKELITE
letter scale

maker: unknown, Germany bruine lijn

bakelite letter scale, Germany 1933-1939

This bakelite letter scale comes from Germany, it has no brand or maker's name. However, there are markings on the bottom of the letter plate and on the inside of the scale housing. In the MPBD molding mark is a code to identify the factory where the product was molded, and an identifying code for the molding material used. This "MPBD" molding mark contains the stylized initials M and P, they stand for Material and Prüfung (German for material and rtesting or research). The mark also contains the stylized capitals B and D, they stand for Berlin and Dahlem. The German MaterialPrüfungs Institute was located in the Dahlem district of Berlin. This coding system to identify maker and material was introduced in 1924 by the German MaterialPrüfungsamt zu Berlin-Dahlem, it was used until 1960. In 1988 a similar code system was introduced internationally, the Resin Identification Code (Source: Molding Marks). On this website you find extensive lists with the meaning of the codes. 45 is Presswerk-AG from Essen. The capital S means Phenolharz mit Holzmehl als Füllstoff, translated Bakelite with sawdust filling. P_AG in a circle is the own logo of Presswerk AG from Essen and is also on the bakelite parts.
I do not know which firm sold this letter scale. It is easy to turn around the postal

back of the letter scale

rates card and change it at rate changes. The information where a new postal rate card had to be purchased is missing. The German postal rates on the card photographed here were valid in the period from December 1, 1933 to May 1, 1939.
This model is more familiar in the implementation as kitchen scales, the Back-Waage of Dr. Oetker. The Dr. Oetker Company has released other scale models, see for example this Oetker kitchen scale, also of bakelite, and this the much more modern plastic Dr. Oetker Backwaage. There are more. Bakelite was also used elsewhere in scales, see for example this letter scale with a bakelite letter plate, this Testut letter scale, this Lightning egg grader, andn this egg scale of Guerin-Brimac.
Below some more pictures of this special letter scale of bakelite.

the card with the postal rates
placed in the slots of the holder

with an empty postal rate card holder

the postal rates card placed
in front of the holder

front of the postal rate card valid from 12-01-1933 to 05-01-1939

back of the postal rate card

side view left	three cover plates on the bottom	side view right
subdivided per gram up to 30 grams	above 30 grams a subdivision per five grams	the weighing range is 500 grams
subdivided per gram up to 30 grams	the weighing mechanism with two springs	the mechanism placed next to the scale housing