Incuse design elements on error coins stem from many causes.
Clashed dies, dropped fillings and brockages constitute three of the
more familiar categories.
Sometimes incuse elements are mirror-image (facing backward and
reading backward) and sometimes they’re normally oriented (facing the
same way as the normal design). It’s rare when you find both
orientations on the same face.
Such is the case with a 1982 Lincoln copper-alloy cent submitted
by James Zimmerman. Struck through an obverse die cap (a previously
struck coin adhering to and blocking the face of a die), it carries a
sharp but incomplete mirror-image version of the reverse design on the
obverse face. The incuse elements show no expansion or distortion.
Running down Lincoln’s coat is an incuse, normally oriented version of
Unusual sequence of events
An unusual sequence of events lies behind this unusual
juxtaposition of forward- and backward-facing design elements. It
began with a late-stage obverse die cap whose floor was greatly
thinned from repeated strikes against a succession of planchets. If
any design ever was present on the working face of the cap, it long
ago had been erased by the ceaseless pounding. A late-stage obverse
die cap will generate a mushy, raised ghost image of the obverse design.
The next step involved the cap coming loose and rotating about 45
degrees clockwise. A rotated, late-stage die cap will ordinarily leave
an extensive set of normally oriented incuse design elements. As a die
cap pounds away at the planchets fed in beneath it, the areas of the
cap covering the field portion of the die are left thinnest. The
remaining areas, which have molded themselves to the recesses of the
die, are thicker because the effective striking pressure is lower
here. When a cap is dislodged and shifts out of position, those
thicker areas are driven into the next planchet, creating the incuse
elements, such as the incuse 1982 date on Lincoln’s coat.
Conventional rotated cap strike
A conventional rotated cap strike is illustrated by a 1991 Lincoln
cent. Two complete sets of incuse elements lie on top of the raised
ghost image. The two sets of incuse elements were caused by two
shift-and-strike events where the die cap was dislodged and rotated
twice, being struck into the surface.
Dislodged die caps can rotate, shift laterally, or both. The last
eventuality is displayed in a 1990 Lincoln cent struck by an obverse
die cap that rotated 180 degrees and shifted toward the north. One set
of normally oriented incuse design elements was generated. (Other
sources of normally oriented incuse design elements are discussed in
the Nov. 3, 2008, Collectors’ Clearinghouse column.)
The third step leading to the formation of Zimmerman’s cent
involves the rotated cap clashing with the reverse die. The clash
obliterated most of the thickened areas of the cap base that would
have otherwise generated normally oriented incuse elements. Only the
thickened area responsible for the date survived, undoubtedly because
the area of the die behind it was deeply recessed.
When a late-stage obverse die cap clashes with the reverse die, it
picks up an incomplete version of the reverse design. Only those
portions of the cap backed by the field portion of the die tend to
pick up an impression. When the die cap strikes the next planchet, it
creates a clashed cap strike, a type of brockage.
Simple clashed cap strike
A simple clashed cap strike can be seen on a second 1982 Lincoln
cent provided by Zimmerman. A minimally expanded, incomplete incuse
impression of the Lincoln Memorial flanks the raised ghost of Abraham
Lincoln. Clashed cap strikes were previously treated in the Aug. 30,
2010, and Sept. 26, 2011, Collectors’ Clearinghouse columns.
Zimmerman’s atypical 1982 Lincoln cent (the first described) was
struck immediately after the rotated cap clashed with the reverse die.
Flanking the ghostly bust of Lincoln are the right and left sides of
the Lincoln Memorial. Many incuse, mirror-image letters from the
reverse design can be seen around the perimeter of the obverse face.
In summary, the genesis of Zimmerman’s unusual 1982 Lincoln cent
involved four steps.
Step 1. Formation of a late-stage obverse die cap.
Step 2. Rotation of the late-stage die cap.
Step 3. The rotated, late-stage die cap clashes with the reverse
die when a planchet fails to be fed into the striking chamber.
Step 4. A planchet is struck by the rotated, clashed cap.
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not accept coins or other items for examination without prior
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