The most common and the most regular form of peripheral die damage
is the die attrition error.
A die attrition error develops when a horizontally misaligned
hammer die smacks repeatedly against the beveled entrance of the
collar. The outer margin of the die face gradually wears away, leaving
the coin with a featureless crescent. A die attrition error will
appear on coins only after the hammer die has returned to a centered
position. While the die is misaligned (and producing misaligned die
errors), the eroded part of the die face lies beyond both the confines
of the striking chamber and the edge of the planchet (see Collectors’
Clearinghouse, Jan. 4, 2010, and Aug. 13, 2012).
1991-P quarter dollars
An extensive die attrition error can be seen in the northwest
quadrant of the illustrated 1991-P Washington quarter dollar. The
letters of LIBERTY have been severely truncated.
The steady removal of metal from the outer margin of the die face
should theoretically result in a progression of coins in which the
unstruck crescent grows steadily larger. But such progressions are
extremely difficult to locate.
A second 1991-P Washington quarter dollar initially held promise
as an earlier stage in the erosion of the die that struck the first
illustrated piece. The featureless crescent is in the same location
but is much thinner and has just begun to encroach upon LIBERTY.
However, this coin shows much heavier die flow lines, indicative of a
later die state. It’s clear that this coin was struck by a different
die pair. Of course, there remains the possibility that it was struck
in the same press before the installation or after the removal of the
die pair that struck the first coin.
Difficulty in assembling die attrition progressions may in part be
due to the rarity of such errors (they’re much rarer than marginal die
breaks or “cuds”). Since die attrition errors are often misidentified
as cuds (as well as other error types), many examples of this form of
error are likely dispersed among a variety of unrelated categories.
Small and early-stage die attrition errors easily escape notice,
making it less likely for the earlier stages of a progression to make
it into anyone’s collection.
Finally, there doesn’t seem to be that much interest in this error
type, so little effort has gone into assembling progressions.
2000-P Virginia quarter dollars
I have managed to assemble one die attrition progression that
consists of a series of 2000-P Virginia quarter dollars.
The progression confirms the causal mechanism described earlier.
The progression was drawn from an extensive run of striking errors
produced by a press beset with numerous problems (see Collectors’
Clearinghouse, Sept. 27, 2010). Errors produced by this press include
off-center strikes, horizontal misalignments of the hammer (reverse)
die, coins incorporating both errors, and coins documenting a
horizontal misalignment of the anvil (obverse) die and collar.
All of the coins are either broadstruck (struck out of collar) or
show a partial collar. The striking chamber was filled with debris,
producing a steadily growing roster of die scratches. This allowed me
to identify six die stages (A to F), although I expect several
additional stages could exist (for more information, see the
March/April 2005 issue of Errorscope, the bimonthly journal published
by the Combined Organizations of Numismatic Error Collectors of America).
Three stages illustrated
The first photograph from this progression shows the southwest
quadrant of an example struck when the hammer die was centered and the
anvil die was misaligned. It represents Die Stage A. At this stage
only a little bit of the field portion of the die has been worn away.
The next example represents Die Stage E. This coin was struck with
the hammer die misaligned toward the southwest — the same area that
the die attrition error is developing. The obverse die was centered.
The final example of Virginia quarter dollar illustrated
represents Die Stage F. When this coin was struck, the hammer die had
returned to center and the anvil die was once again horizontally
misaligned. The die attrition error has grown so that the field
portion of the die has been worn away as far as the bottom of the
letters of E PLURIBUS.
I have not seen any examples from this series that show the
letters truncated, so this might represent the maximum extent of attrition.
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