Part V. Planchet Errors:

Bimetallic Errors:

Wrong ring

Definition: A bimetallic planchet that is assembled using the correct core but the wrong ring. Bi-metallic error coins are restricted to foreign countries. These coins may experience any of the many types of striking errors listed in the Error-Variety Ready Reference however, one must understand we are dealing with two components, a ring and a core. Any number of exotic possibilities or combinations of die varieties, die errors, planchet errors and striking errors can be found on bi-metallic coinage. These errors are unequivocally rare.

There are any number of sources for the incorrect ring.

1. It might be a ring that was intended for a different bimetallic denomination
   with a similar-sized hole.
2. Punched out of stock intended for a different bimetallic denomination.
3. Punched out of stock intended for a solid-alloy denomination.
4. Punched out of stock intended for the core.
5. An inadvertently holed, solid-alloy blank or planchet intended for another
   denomination.
6. A previously-struck, solid alloy coin that was accidentally holed.

This 2001 British 2 pound coin has a normal copper-nickel core surrounded by a steel ring instead of the expected nickel-brass ring. The steel ring is substantially thinner than both the core and normal ring, which is why so few peripheral design elements appear on it. The steel ring weighs an estimated 2.6 grams instead of the normal 5.9 grams. The edge of the off-metal ring displays a few letters of “ON THE SHOULDERS OF GIANTS”. This shows that the composite disc passed through the appropriate edge-lettering device and that its original external diameter was close to that of an assembled 2 pound blank.

The center hole was presumably punched to normal diameter, since British 2 pound bi-metallic blanks are pre-assembled. The hole’s offset position may be partly due to the slightly undersized steel disc occupying an uncentered position within the hole-punching device. The offset appearance was accentuated by uneven expansion of the core during the strike, which split the ring at 9:00.

The ring on this British 2 pound coin was derived from a worn, battered, and discolored Hong Kong dollar (1993-1998). Composed of a solid copper-nickel alloy, this coin had its center punched out and filled with a British 2 pound core. A misaligned hole, combined with uneven expansion of the core, caused the ring to split at 10:30 when it was struck by the 2 pound dies. The edge of the ring carries no edge lettering. It either bypassed the edge lettering device or was too small to betray its passage through the device.

A two pound 2006 Isambard Brunnel from Great Britain. The ring is is strongly attracted to a magnet. (Either elemental nickel or steel composition). Weight: 10.30 grams.

Note the following specification information regarding U.K. outer rings: 12.0 g is normal weight for a bi-metallic of this series. A two pound ring consists of the following composition and weight: Two pound ring 76% Copper, 4% Nickel, 20% Zinc Weight – 6.0 g

A two pound Technology from Great Britain. Ring is strongly attracted to a magnet (steel ring). The ring also has a misaligned center hole. The ring is much thinner than the core resulting in the near incomplete absence of design transfer on either face of the ring. The ring also sheared & snapped when struck.

A two pound 2007 Gun Powder Plot from Great Britain with wrong ring. The ring also has a misaligned center hole. The ring is thinner than the core resulting in the absence of some design transfer on either face of the ring.

Part V. Planchet Errors:

Wrong Planchet and Off-Metal Errors:

Double Denomination Errors:

Struck Over Pre-Existing Wrong Planchet/Off-Metal Error

Definition: A design struck over another design (either domestic or foreign) which was, in turn, struck on the wrong planchet.  Such errors are quite rare, with a significant proportion intentionally fabricated inside the mint.

This state quarter design was struck over a 2000-P nickel design which had been, in turn, struck twice on a cent planchet.  The quarter strike was off-center and has a first-strike brockage of the obverse quarter design on its reverse face.  This error may have had some assistance in its creation.  Photos courtesy of Terry Holcomb.

This 2004 Canadian cent design was struck over a 2004 Papua New Guinea 1 tohea design which had itself been struck on a Fiji one cent planchet.  The coin was cherrypicked from eBay by James Zimmerman, who expended a great deal of time and effort in identifying the host coin design and the original purpose of the planchet.  This seems to be a truly accidental error.  Photos courtesy of James Zimmerman.

This 1983 Canadian cent design was struck on an Israel 10 shekels design which was originally struck on a Canadian 1 cent planchet.  As such, the final strike generated a dual country / double-denomination error but not a wrong planchet error.  This is almost certainly an intentional error because it was struck in-collar.  The original off-metal coin would have to have been resized after the first strike, which would have caused the coin to expand beyond the diameter of the collar.  Photos courtesy of Fred Weinberg.

This 1982 Costa Rica 25 centavos design was struck over an Israel 10 shekels design which had originally been struck on a Costa Rica 25 centavos planchet.  As with the previous coin, the final strike generated a dual country/double denomination error but not a wrong planchet error.  And as with the previous coin, the last strike was in-collar, which would have required resizing of the expanded off-metal 10 shekels.  Photos by Mike Diamond

PART V: Planchet Errors:

Wrong Planchet and Off Metal Errors

Definition: A wrong planchet error is exactly what the name indicates – a coin struck on a planchet intended for another denomination (domestic or foreign).  The incorrect planchet may have the same composition (e.g. a quarter struck on a dime planchet) or it may be a different composition (e.g., a quarter struck on a nickel planchet).

An off-metal error is a coin struck on a planchet whose composition does not match the composition that normally characterizes the coin.  While off-metal errors can be wrong planchet errors, this is not always the case.  For example, a dime struck on a copper core is off-metal but is not really a wrong planchet.

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A Sacagawea planchet somehow found its way into the coin press that was striking  1999-P Susan B. Anthony dollars.

This coin is comes to us courtesy of Mark Lighterman

Images were taken through an encapsulation.

Part V: Planchet Errors:

Wrong Stock:

Off-Metal

Photos courtesy of Heritage Auctions.

PART III. Die installation Errors:

Mules: 

Wrong anvil die

Definition: Mules are coins struck by mismatched dies. In this case the wrong anvil die was installed in a coin press.

This Malaysian 10 sen mule was struck on a 10 sen planchet in a reeded 10 sen collar and carries a normal 10 sen obverse. The reverse face was struck by a 1 sen reverse (anvil) die.

This dual denomination mule was struck in 1993 by the Denver mint. It had the correct hammer die (cent die) and the coin was struck on the correct planchet. However, the anvil die (dime die) was mistakenly installed in the coin press which resulted in this unique combination.

This dual denomination mule coin was struck in 1999 by the Philadelphia mint. It had the correct hammer die (cent die) and the coin was struck on the correct planchet. However, the anvil die (dime die) was mistakenly installed in the coin press which resulted in this unique combination.

Images courtesy of Heritage Auctions

PART III. Die Installation Errors:

Mules: 

Wrong hammer and anvil die

Definition: Mules are coins struck by mismatched dies. In this case both hammer and anvil dies were not correct.

This Malaysian mule would be classified as a “double mule” It was struck by a 1 sen obverse die and a 1 sen reverse die installed in a 10 sen press. The coin was struck on a copper-nickel 10 sen planchet inside a 10 sen collar and shows the reeded edge normal for the 10 sen denomination (the 1 sen coin has a smooth edge).

PART III. Die Installation Errors:

Mules:

Wrong hammer die

Definition: Mules are coins struck by mismatched dies. In this case, the wrong hammer die was installed in a coin press.

The 2005 Malaysian mule shown below was struck on a copper-nickel 10 sen planchet inside a reeded 10 sen collar and features a normal 10 sen reverse design. The obverse (struck by the hammer die) shows an unexpected and appreciably smaller 1 sen design. This resulted in a weakly struck periphery on the reverse face. A normal 1 sen coin is copper-plated steel.

PART III. Die installation Errors:

Mules: 

Wrong anvil die

Definition: Mules are coins struck by mismatched dies. In this case the wrong anvil die was installed in a coin press.

This Malaysian 10 sen mule was struck on a 10 sen planchet in a reeded 10 sen collar and carries a normal 10 sen obverse. The reverse face was struck by a 1 sen reverse (anvil) die.

This dual denomination mule was struck in 1993 by the Denver mint. It had the correct hammer die (cent die) and the coin was struck on the correct planchet. However, the anvil die (dime die) was mistakenly installed in the coin press which resulted in this unique combination.

Images courtesy of Heritage Auctions.

This dual denomination mule coin was struck in 1999 by the Philadelphia mint. It had the correct hammer die (cent die) and the coin was struck on the correct planchet. However, the anvil die (dime die) was mistakenly installed in the coin press which resulted in this unique combination.

Images courtesy of Heritage Auctions

PART V. Planchet Errors:

Wrong Planchet and Off-Metal Errors:

Foreign Denomination struck on a U. S. planchet.

Definition: Through most of its history the U.S. Mint has struck coins for other countries.  Occasionally a domestic planchet would pass through a coinage press striking coins for another country.

Foreign denominations can also be struck on domestic planchets when a foreign mint has been contracted to supply planchets to the U.S. Mint.  Canada has occasionally supplied nickel planchets to the U.S. Mint and so we sometimes find Canadian coins struck on these nickel planchets.

The 1970 Philippines 25 sentimos shown above was struck in the U.S. Mint on a domestic cent planchet.  In 1970 the Denver and San Francisco Mints each struck 20 million 25 sentimos coins for the Philippines government.

This coin is in the collection of Jim Zimmerman.

The 1972 Philippines 1 Peso shown above was struck in the U.S. Mint on a domestic clad 50 cent planchet.  In 1972 the Denver Mint struck just under 122 million, 1 Peso coins for the Philippines government.

This coin is in the collection of Jim Zimmerman.

In 2000 the Royal Canadian Mint supplied the U.S. Mint with nickel planchets.  One of these planchets, shown here, passed through a press striking the January, 2000 Canadian Millennium-series quarter dollar.

This coin is in the collection of Jim Zimmerman.