Dating Zippo Lighters:

   1932 - First model created by George Blaisdell. It is about one quarter inch longer than later models.

   1933 to 1935 - The hinge connecting the top and bottom of the lighter case is soldered onto the outside of the case. The hinge is made up of 3 barrels - one center, usually connected to the bottom hinge plate and 2 outside, connected to the top hinge plate.  The bottom of the lighter case is flat and the edges are squared off. The windscreen has 16 holes and the cap pressure bar pivot pin area is a part of the windscreen.

   1936 - The hinge is still soldered onto the outside of the case and is made up of 4 barrels.  The bottom of the lighter case is still flat and the edges are squared off.

   Mid to late 1936 to 1943 - The hinge is now soldered on the inside of the case and is made up of 4 barrels.  The bottom of the lighter case is still flat and the edges are squared off or rounded. 1937 is the beginning of the brass drawn case with a more rounded top and bottom. Formerly, the top was flat and soldered into place.

   1943-1945 - The hinge is made up of 3 barrels.  The bottom of the lighter case is slightly rounded and the edges are rounded.

   1946-1950 - The bottom of the lighter case is changed. It has a concave framed look, that is, there is an indented area where the imprint is located and the edges are rounded. In 1946, the windscreen is made with 14 holes. In 1947, the windscreen is made with 16 holes and the metal supporting the wheel now connects to the top of the windscreen. The words ZIPPOMFG, on the inside unit have no space between ZIPPO and MFG.

   1951 forward - The hinge is made with 5 barrels.

   1953 forward - The patent number is changed to 2517191 from 2032695.