Struck-through errors assume myriad forms reflecting the wide
variety of foreign objects and substances that end up being struck
into coins. The extent and location of struck-through errors is also
It is therefore no surprise that impressions left by foreign
matter seldom respect the boundaries of the design. This is especially
true of discrete flakes and fragments. Their positioning in the
striking chamber is random so it’s highly unlikely that the edge of a
fragment will precisely coincide with the edge of a design recess in
the die face.
When it comes to die fill (“grease”) the constraints are a bit
different. Die fill forms a relatively amorphous mass that tends to be
slowly-accumulating and slowly-diminishing. These properties can lead
to die fill pooling in design recesses without slopping over onto the
field portion of the die. The term “filled die error” is often applied
to the pinpoint loss of design elements caused by this mechanism.
The expectation of unpredictable positioning for compact
struck-through errors is confounded by cases in which the impressions
are confined to the field and end right at the edge of the design.
Our first example of such a conundrum is a 2007 Lincoln cent with
numerous small struck-through errors, most of which appear to the
right of Lincoln’s head. One pit is located to the left of his head
and an interior pit is found along the jaw line. The pits are
well-organized, with a clear northwest-to-southeast orientation.
Many of the pits are elongated in the same direction. The pits are
sprinkled within a larger zone that is less reflective than the
normal, die-struck field. It would appear that a smoothly textured,
thinly applied substance spanned the gaps between the more discrete
elements studding the die face.
A very similar error is seen on a 2008 Lincoln cent. The debris
patch is located in the same area of the coin and has the same
northwest-southeast directionality. The debris patch terminates
abruptly on both sides of Lincoln’s head. Once again, many of the pits
are elongated in the same direction as the debris patch.
I have seen a number of other recent cents with the same pattern
of struck-through errors. The same debris patch can appear on multiple
coins struck by the same die pair, indicating that the debris was
firmly attached to the die face.
In all such errors it would appear that a gritty paste was smeared
onto the die face by a moving machine part, most likely the
feeder/ejection mechanism. An apt analogy would be a butter knife with
a little bit of chunky peanut butter clinging to its blade. If you
drag the knife over a slice of bread with large gas pockets, the
peanut butter will only stick to the outer surface of the bread. The
holes in the bread, like the recesses of the die, will not be filled
by the peanut butter.
Both the 2007 and 2008 cents were struck by inverted dies (obverse
die as anvil die). The anvil die is more likely to be smeared with
paste since the feeder/ejector slides across the anvil die face during
Further evidence for the gritty paste conjecture can be found in a
large series of broadstruck 2003-P Arkansas quarter dollars provided
by error dealer Fred Weinberg. These coins were also struck by
inverted dies, but it is the hammer (reverse) die that is more
strongly affected and the directionality of the debris patch is reversed.
Our first example from this sample shows a broad debris patch on
the reverse face that extends in a northwest-southeast direction.
Numerous elongated (and often contiguous) pits appear in the field,
around and between the raised design elements. Aligned with the
irregular pits are an abundance of fine, parallel die scratches.
Evidently, the feeder/ejector scratched the reverse die face. The
obverse die also shows fine, parallel die scratches arranged in the
same direction (southwest-northeast) as those on the reverse face. The
encrusted feeder/ejector must have damaged both dies but only
deposited the gritty paste on the hammer die.
A second example from this group shows feeder/ejector damage to
the coin after the strike. Severe scrapes in the southwest quadrant of
the obverse face are perfectly aligned with the die scratches.
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