A wrong stock error emerges when a strip (coil) of coin metal
intended for one denomination is sent through a blanking press
punching out blanks for a different denomination. The resulting blanks
are eventually struck with the design and denomination appropriate to
the diameter of the blank. A quarter dollar struck on a planchet
punched from dime stock would be one example (Collectors’
Clearinghouse, Feb. 20, 2012).
The vast majority of wrong stock errors involve a blank with a
metallic composition no different from the denomination it eventually
carries. For example, after 1964, a dime, a quarter dollar and a
quarter dollar struck on dime stock all have a copper-nickel clad
composition. Only a few off-metal, wrong stock errors have been
identified. This makes intuitive sense, because it’s easy to mix up
coils that are identical in every respect except thickness. But a coil
whose surface or edge color deviates markedly from the normal coil
will usually be detected.
The best known off-metal, wrong stock error is represented by
fewer than a dozen 1987-P Jefferson 5-cent coins struck on
copper-nickel clad quarter dollar stock (see photo). Since quarter
dollar stock is thinner than 5-cent stock, these coins are predictably
and consistently underweight at 4.2 grams (a normal 5-cent coin weighs
Our next Jefferson 5-cent coin carries no date and was struck
off-center on a copper-nickel clad planchet, the unstruck portion of
which terminates in a straight clip. The copper core is visible on
both the planchet’s unstruck edge and along the outer margin of the
struck tongue where it has extruded past the surrounding clad layers.
Although its weight, diameter, and thickness have not been recorded,
Jon Sullivan reports that its diameter seems to match that of a 5-cent
planchet and its thickness seems consistent with quarter dollar stock.
I suspect the blank that became this coin was derived from the leading
edge of the same strip that gave rise to the 1987-P Jefferson 5-cent coins.
A number of other coins (many from the 1990s, and mostly 5-cent
coins) are struck on anomalous clad or purported clad planchets.
However, their size, weight and general appearance do not match the
expectations for stock belonging to any known clad denomination
(Collectors’ Clearinghouse, Feb. 13, 2012).
The last off-metal, wrong stock error is the most complex.
Recently brought to light by Fred Weinberg, it’s a 1971-D Washington
quarter dollar struck off-center on a quarter dollar-sized,
straight-clipped blank that weighs 2.4 grams. Numismatic Guaranty
Corp. lists its composition as 80 percent silver and 20 percent
copper. This metal ratio is found in the clad layers of half dollars
struck between 1965 and 1970 and in physically identical half balboa
coins struck on behalf of Panama by the San Francisco Assay Office
between 1967 and 1972. As expected, darker core material is
asymmetrically exposed along the edge of the coin’s unstruck upper
corner. The grayish core presumably shares the 79 percent copper and
21 percent silver ratio found in the similarly gray cores of
silver-clad half dollars.
It turns out that this 1971-D quarter dollar was not simply struck
on obsolete half dollar stock or contemporary half balboa stock.
Thickness of the unstruck portion looks about the same as a quarter
dollar blank (1.75 millimeters). It would appear that a coil of coin
metal intended for 1970-D half dollars or 1971 half balboas was
mistakenly rolled to quarter dollar thickness and labeled as quarter
dollar stock. This coil was eventually fed into a blanking press
punching out quarter dollar blanks.
One of those blanks made it as far as a quarter dollar press. The
straight clip indicates that the blank is probably derived from the
leading edge of the strip.
The scenario I’ve presented is not as unlikely as you’d think.
Since 1965, the Denver Mint facility has been the primary source for
wrong stock errors, along with generic rolled-thin and rolled-thick errors.
Wrong stock errors from the period surrounding this particular
error include 1970-D and 1971-D Washington quarter dollars struck on
dime stock, 1970-D Roosevelt dimes struck on quarter dollar stock, and
1971-D Kennedy half dollars struck on quarter dollar stock.
Rolled-thin errors of varying severity affect silver-copper clad half
dollars in every year of their production except perhaps 1970, when
they were produced solely for Uncirculated Mint sets by the Denver Mint.
Coin World’s Collectors’ Clearinghouse department does
not accept coins or other items for examination without prior
permission from News Editor William T. Gibbs. Materials sent to
Clearinghouse without prior permission will be returned unexamined.
Please address all Clearinghouse inquiries to firstname.lastname@example.org or to
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