Komomir Semenova "KI", 1931, Head №2437
Komomir Semenova "KI", 1934, Head №14713
The Krasny Instrumentalnik (KI) plant began producing meters in Leningrad (USSR) in 1931.
In the Museum of Industrial Tools MICROTECH there are rare 2 Semenov protractors, which were made in the first years of their production (1931 and 1934).
The protractors are named after the engineer-inventor (modern names of this type of protractors "UN-127" and "type 2"), on both protractors of the Semenov system the number of the author's certificate №26643 is engraved.
It should be noted that Semenov's protractors are considered one of the most successful Soviet developments of the meter, but we found a much earlier US patent US№ …… .. identical protractor, which confirms the general trend of compiling an absolutely larger number of Soviet meters from Western and American patents and serial samples.
There is no information in the available literature about the inventor Semenov and his attitude to the Leningrad "KI", which is quite typical of the Soviet history of science. It is possible that the inventor of the Semenov protractor did not correspond to the class or national filters of the USSR according to the questionnaire, so his name is not mentioned in the history of the KI (Leningrad) and Caliber (Moscow) plants, which mass-produced Semenov protractors for over 60 years.
The difference between the factory numbers of the protractors allows us to estimate the average annual program of production of protractors Semenov (2500..4100 pcs / year).