Around the late 70's the logo was redesigned again, but not implemented into the bottom stamp until 1980.
In July of 1986, lot codes were also being included on all Zippo lighters, showing the month and the year of production.
The “Block” Zippo was used from 1933 to 1954; it was changed to the “Script” Zippo in 1955, and the “Flaming i” began in 1980. Pending was stamped from 1933 until the end of 1936, when it was replaced with Pat. We’ve provided examples of what we believe to be the correct bottom codes for those tricky years.
Again, placement of the wording, the material the case is made of and the number of barrels on the hinge play key factors in dating earlier Zippo lighters.
The letters A-L on the left side of the Zippo logo represents the month that the lighter was manufactured (A = January, B = February, etc.), the year is identified by the last two numbers on the right of the Zippo logo.
George Grant Blaisdell established Zippo in October 1932 in Bradford, Pa., and the first Zippo lighter was produced in January 1933.
In 2002, the holes in the chimney of slim lighters were enlarged.
Dating Zippo lighters produced in Canada from 1950 until 1986 is difficult due to the lack of date coding.
I have seen some earlier stamping 1954 zippo cases, with this later insert, showing that zippo was using up all the older cases during late 1954.
Pour 2001 et après, Zippo a introduit une nouvelle nomenclature plus facile à interpréter.
The Zippo Manufacturing Company started featuring at the bottom of the lighter case, on the left side of the logo, the month code in the center, and the year stamped in Roman numerals (XVI).