1939 Development completed on the 51st anniversary of the Parker Pen Company.

1939-40 Parker “51” test-marketed in South America and Caribbean countries.

1940 Parker “51” test-marketed in selected U.S. cities.

1941 The Parker “51” is introduced in the U.S. market.

Known as First Year model.

1941 Parker “51” Ink introduced

1946 Parker “51” Red Band filler introduced and made for approximately one year

1947 Parker “51” Parker 51 Vacumatic introduced in UK

1947 Parker “51” vac demi introduced and made for 2 years

1947 Plain arrow clip introduced

1947 Blue Diamond clip discontinued mid-year

1948 Last year for vacumatic “51”

1948 Last year for vacumatic demi Parker “51”

1948 Aerometric Filler Parker “51” in demi and full sizes

1948 Parker “51” Signet in all gold filled cap and barrel

1948 Superchrome Ink introduced

1949 Parker “51” Presidential in all 14kt cap, barrel and clip

1949 Parker “51” Flighter in all stainless cap and barrel with gold cap band

1950 Parker “51” Special introduced

1950 Parker “51” Aerometric introduced in UK

1951 Arrow clip shortened

1952 Last year for barrel dating on pens

1954 Parker “51” Jotter ballpoint introduced

1955 Liquid Lead pencil introduced

1956 Last year for pencil dating

1957 Rotary pencil introduced for regular “51s”

1957 Last year for Superchrome on filler sleeve

1958 “Signet” model renamed the “Insignia”

1958 “Bandless” Flighter introduced and made through 1960

1958 Parker “halo” logo added to cap

1960 Breather hole moved to the side of barrel

1961 Demi model discontinued

1961 Converter version introduced; only made for approximately two years

1962 Finger clutch introduced

1964 Cap “lip” removed

1965 “51” imprint on cap

1965 New one-piece filler sleeve without black plastic end cap

1969 MKII introduced; “61” look-alike with pearl jewel cap, greater barrel taper, flat end

1971 MKIII introduced; same as MKII but with chrome jewel

1972 Parker “51” discontinued in UK

1978 Parker “51” discontinued in USA

* Years are as close as possible, but it must be noted that most changes often took place over a period of months. It is also very common to find pens that have been fixed over the years and have parts exchanged with earlier or later models