Document enfin trouvé: Pour mon lowlight 2N
2 : février
N: Année 57
Parts are stamped with a 2 or 3-digit sequence.
From 1920-1963, the format was 1 or 2 numeric digits, then an alpha character.
The first 1 or 2 digits are the month, 1 through 12.
The last digit, a letter, is the year.
I was not used as they are too similar to the month digits.
For 1945-1963, O was also not used for the reason above.
From 1920-1944, the following apply:
A=1920 B=1921 C=1922 D=1923 E=1924 F=1925 G=1926 H=1927 J= 1928 K=1929 L=1930 M=1931 N=1932 O=1933 P=1934 Q=1935 R=1936 S=1937 T=1938 U=1939 V=1940 W=1941 X=1942 Y=1943 Z=1944
For 1945-1963, the following apply:
1945=A, 1946=B, 1947=C, 1948=D, 1949=E, 1950=F, 1951=G, 1952=H, 1953=J, 1954=K, 1955=L, 1956=M, 1957=N, 1958=P, 1959=Q, 1960=R, 1961=S, 1962=T, 1963=U
Example: 8M would be August, 1956:
For 1964-1969, Bosch used a 3-digit numbering scheme. The first digit is the last number of the year. The second 2 digits represent the month.
Example: 401 would be January, 1964.
For 1970-79, Bosch continued using a 3-digit numbering scheme but the months were numbered 21-32. In addition, 33-36 were used for the 4 quarterly periods. 33 = Jan.-March, 34 = Apr.-June, 35 = July-Sept., 36 = Oct.-Dec.
021 = January, 1970
932 = December, 1979
436 = 4th quarter, Oct.-Dec., 1974