Historical and technical guide
Technical insert clues, photographed views and overlapping historical periods.
All illustrated examples and dated claims link back to their original documented references and named sources. Transitional dates are approximate unless explicitly supported.
Terry Lyons photo reference: the photographed case and insert are plain (unplated) nickel silver. Chrome-plated nickel-silver case finishes also appear in late 1946, so the material/finish alone is not an exact-year code.
Terry Lyons photo reference: chrome-plated nickel-silver case with nickel-silver insert. The photographed insert has a MODERN replacement cam spring as documented by Terry Lyons; never use this spring as evidence of a 1947 factory construction.
Terry Lyons photo reference: chrome-plated brass case and nickel-silver insert. Brass reappeared in the postwar transition; confirm multiple construction features and allow overlap.
Terry Lyons photo reference: chrome-plated brass case and nickel-silver insert. A three-barrel hinge is documented here but the hinge transition is not a strict 1 January production cutoff.
Niagara Falls production began on 19 August 1949. Early Canadian cases and inserts use PAT. PEND. wording.
A real 1956 Bradford example supplied by Terry Lyons documents a brass case with steel insert and provides a photographed dot-layout comparison.
Zippo begins production of Slim lighters. Early Slims have a flat bottom; the insert uses a wheel guard (“cobra head”) over the flint wheel.
Canadian hinge transition: unequal five-barrel spacing is generally treated as 1956 and later.
Terry Lyons photographic reference: Bradford regular case attributed to 1972, with documented 1 left / 1 right vertical bars date marks. Original bottom-stamp and insert front/back/chimney photographs available. The insert may have been replaced; check the complete evidence before identifying an exact production date.
A lower-hinge bevel change is reported from April.
Insert reference · 1932
Insert reference · 1933–1936
Insert reference · 1936–1942
Insert reference · 1942
Insert reference · 1943–1945
Insert reference · 1943–1946
Insert reference · 1946
Insert reference · 1946–1947
Insert reference · 1946–1948
Insert reference · 1947
Insert reference · 1947–1951
Insert reference · 1948
Insert reference · 1948–1951
Insert reference · 1949
Insert reference · 1949–1950
Insert reference · 1950
Insert reference · 1951
Insert reference · 1951–1953
Insert reference · 1951–1958
Insert reference · 1952
Insert reference · 1953
Insert reference · 1953–1956
Insert reference · 1954
Insert reference · 1955
Insert reference · 1956
Insert reference · 1956–1958
Insert reference · 1957
Insert reference · 1958
Insert reference · 1958–1959
Insert reference · 1959
Insert reference · 1959–1960
Insert reference · 1959–1963
Insert reference · 1960
Insert reference · 1961
Insert reference · 1961–1967
Insert reference · 1962
Additional matches are available in the full archive.