Here is what I have, hope it helps.
Bridgeport Milling Machine Serial Numbers
The machine serial number is located on the knee casting. Standing in front of the machine, crank the Y axis
handle to move the saddle to the rear of its travel. The sliding guards will move to the rear exposing the
stamped number. Most serial numbers start with a "12/BR" which signifies a 12" Y axis travel, however, for
earlier machines, pre 60's, the serial numbers start with "BR" which signifies a 9" travel.
The numbers were started in 1938 with #1 and today are close to the 300,000 mark. The 50,000 mark was
passed in the 1960's and the 200,000 mark in the 1970's. The 1980's and 1990's have brought the numbers
close to the 300,000 mark. Along with the machine serial number each milling head is numbered. They are
stamped on the main housing and also on a tag on the upper drive. These numbers are prefixed with the
model of the head. The most common are "M", "J", "2J". The M model is a 1/2hp older head that was out of
production sometime in the 1960's. The J head is a 1hp V-belt drive head that was the main work horse for
many years. The 2J variable speed head was first introduced with a 1 1/2hp motor. This was later changed
to a 2hp motor. The 2hp heads have a \2 at the end of the head serial number.
The following is a breakdown of machine s/n's in relation to the dates manufactured.
Year Serial Number
1938 BH-1 thru BH-39
1939 BH-40 thru BH-252
1940 BH-253 thru BH-656
1941 BH-657 thru BH-1549
1942 BH-1550 thru BH-2943
1943 BH-2944 thru BH-4105
1944 BH-4106 thru BH-4997
1945 BH-4998 thru BH-5930
1946 BH-5931 thru BH-7235
1947 BH-7236 thru BH-8814
1948 BH-8815 thru BH-10381
1949 BH-10382 thru BH-11378
1950 BH-11379 thru BH-12750
1951 BH-12751 thru BH-14489
1952 BH-14490 thru BH-16700
1953 BH-16701 thru BH-19367
1954 BH-19368 thru BH-22732
1955 BH-22733 thru BH-26962
1956 BR-26963 thru BR-31618
BH-30023 Last Round Arm BR-30024 First Dovetail Overarm
1957 BR-31619 thru BR-37278
1958 BR-37279 thru BR-42110
1959 BR-42111 thru BR-46938
1960 BR-46939 thru BR-52598
1961 BR-52599 thru BR-58552
1962 BR-58553 thru BR-64987
1963 BR-64988 thru BR-71981
1964 BR-71982 thru BR-79538
1965 BR-79539 thru BR-88180
1966 BR-88181 thru BR-98089
1967 BR-98090 thru BR-108351
1968 BR-108352 thru BR-118640
1969 BR-118641 thru BR-131778
1970 BR-131779 thru BR-138639
1971 BR-138640 thru BR-143350
1972 BR-143351 thru BR-149294
1973 BR-149295 thru BR-157909
1974 BR-157910 thru BR-167652
1975 BR-167653 thru BR-174083
1976 BR-174084 thru BR-180697
1977 BR-180698 thru BR-188559
1978 BR-188560 thru BR-196987
1979 BR-196988 thru BR-206296
1980 BR-206297 thru BR-216473
1981 BR-216474 thru BR-227523
1982 BR-227524 thru BR-231827
1983 BR-231828 thru BR-236110
1984 BR-236111 thru BR-241350
1985 BR-245351 thru BR-245659
1986 BR-245660 thru BR-248551
1987 BR-248552 thru BR-250531
1988 BR-250532 thru BR-252874
1989 BR-252875 thru BR-255463
1990 BR-255464 thru BR-257888
1991 BR-257889 thru BR-259897
1992 BR-259898 thru BR-262187
1993 BR-262188 thru BR-264585
1994 BR-264586 thru BR-267603
1995 BR-267604 thru BR-271109
1996 BR-271110 thru BR-273843
1997 BR-273844 thru BR-276799
1998 BR-276800 thru BR-279106
1999 BR-279107 thru BR-280965
2000 BR-280966 thru BR-283022
2001 BR-283023 thru BR-284382
2002 BR-284383 thru BR-284978