When zoology was in its formative phase, the world was populated by
a host of fantastic animals. Hippogriffs, basilisks and griffins
decorated the pages of medieval bestiaries and were thought to be as
real as giraffes, rhinos and elephants. The world of error collecting
has its own mythological denizens — error types that don’t really
exist. Those described below still lurk within the pages of some
A jam strike is said to be the companion to a unipolar edge
strike. The latter occurs when a planchet or coin is struck on-edge,
but the edge facing the anvil die is blocked by an intervening
planchet. There’s no doubt unipolar edge strikes do occur, but they’re
very rare and difficult to identify.
For a jam strike, the horizontally oriented planchet is said to be
left with an indentation on its upper face (from the edge of the
vertically positioned planchet) and a small island of die-struck
design on its bottom face. The problem with this scenario is that,
after the edge-struck coin springs out of the striking chamber, the
continuation of the downstroke of the hammer die will produce a normal
die-struck design on both faces of the bottom planchet.
A jam strike is a misinterpretation of a rare but well-documented
error — an invisible strike in association with struck-through error
(see the Sept. 20, 2010, column).
An example of such an error is shown here in the form of an
undated 5-cent coin. When this coin was struck the dies were too far
apart to leave an impression. A small circular object took up the
excess space between the dies, leaving a shallow pockmark on the
obverse face and a small island of die-struck design on the reverse face.
Weld seam planchet
According to published accounts, the Philadelphia Mint would, in
some years, create continuous strips of cent stock by fusing the
trailing end of one strip to the leading edge of another strip.
Instead of actually welding the ends together, they were said to be
brazed. Brazing involves melting a filler metal and allowing it to
flow into the gap between two pieces. Before the ends are joined, they
must be trimmed, fitted and cleaned.
On the face of it, there doesn’t seem to be any reason to follow
such a laborious procedure. Individual coils of coin metal are quite
long enough. I have questioned several individuals who visited the
Philadelphia Mint during the time period when brazing allegedly
occurred. None reported seeing the brazing operation or even brazed strip.
Weld seam cents allegedly weigh less than a normal cent and have a
lower density. They are supposed to have a brassy color due to a
higher percentage of zinc. Why the entire coin should be affected
isn’t clear as the seam should presumably be quite narrow.
I have seen three purported examples of this error. The one shown
here, an abnormally thin 1980 Lincoln cent, was originally
encapsulated by Numismatic Guaranty Corp. and identified as a “weld
area planchet.” It is lighter than normal at 2.49 grams and the
reverse face shows an uneven brassy tint. But its density is
significantly greater than that of a normal cent (its specific gravity
is 10.29; it should be 8.83).
I really don’t know what it is, but there’s no reason to think it
was punched out of a brazed seam. Purported weld seam planchet errors
could variously represent improper alloy mix errors, foreign
planchets, foreign stock or nameless “orphan” off-metal errors. If
these errors were real, they should be considerably more abundant, as
the blanking press would always generate a series of blanks from seam area.
beneath an elevated collar
This error is said to occur when the collar rises so high above a
planchet that the bottom face of the planchet extends below the bottom
edge of the collar’s working face. When struck, the coin receives a
reverse partial collar error and has to be manually removed from the press.
This seems quite farfetched. The working face of the collar has to
be as tall as the anvil die neck so that the anvil die can receive the
planchet and later push the newly struck coin into the path of the
ejection finger. The collar would therefore have to rise almost a
centimeter to clear the planchet. In this situation, the hammer die,
having a shorter neck than the anvil die, would not even be able to
reach the planchet. Photos of a cent allegedly created in this fashion
show only a peculiar bump on the edge, but no sign of a reverse
Reverse partial collar errors do occur as a common side effect of
inverted die installation. For current issues, an inverted die setup
(obverse die as anvil die) was introduced as early as in 1992 at the
Purported reverse partial collars that appear on modern issues
before this date have all turned out to be examples of post-strike damage.
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