What is an off-metal? An off-metal is defined as a coin which is struck on the planchet of a different denomination of coin. For example, a Jefferson nickel struck on a Lincoln cent planchet is an off-metal. This error type is found on all denominations of U.S. Coins. Some of the most expensive U.S. error coins are off-metals, and in fact, one of the most expensive error coins is an off-metal 1906 Indian cent struck on a gold Liberty head $2.50 planchet. It sold for $276,000 at a Stacks auction in the summer of last year!A more recent example is an NGC MS-66 1913 type-2 buffalo nickel struck on a dime planchet, which sold in a Heritage auction in April of this year for $46,000.
Above: 1980-P Jefferson nickel off-metal struck on a Lincoln cent planchet. The “damage” is pre-strike damage, and occurred before the coin was struck.
In discussing how this error type occurs, as an example I will use the 1980 nickel struck on a cent planchet as shown. The first step in the creation of an off-metal nickel on cent occurs when a cent planchet becomes lodged in the swinging door or in some nook or cranny of a planchet bin. At the mint, planchet bins are often used for transporting planchets to the different points of production. The bins are used interchangeably for the different denominations of coins, and if a bin has been used for transporting cent planchets, and a planchet becomes lodged in the bin, and if the bin is then used for transporting nickel planchets, the cent planchet could become dislodged and mixed in amongst the nickel planchets. When the nickel planchets are fed into the minting press, the cent planchet will then be struck by the nickel dies, impressing the nickel’s design onto the cent planchet, thus creating a “nickel on cent” off-metal. The nickel on cent will be a slightly larger diameter than a normal cent as a result of the cent planchet mushing outwards when it is struck. Also, the coin will be the correct weight for a normal Lincoln cent, but will have the design of a Jefferson nickel.
The vast majority of off-metals occur in the manner just described, although they can also occur in other ways. One possibility is if a minting press which has been striking cents is switched to striking nickels. If that happened, the dies would be changed in the press, from cent dies to nickel dies, and various other changes would be made to the press. If a cent planchet was accidentally left in the striking chamber after the press had been refitted for striking nickels, and if the press started striking nickels, then the cent planchet would be struck by the nickel dies, thus creating a nickel on cent.
Some off-metals are made with human intervention. Impossibly wild, off-metal combinations exist which completely defy logic, and which could not have been created without the help of someone at the mint. Examples of this include off-metal combinations where the planchet is larger than the design which it is struck upon it–a combination which is impossible at the U.S. Mint without the aid of human intervention, since the planchet feeder tubes of a minting press do not allow for any planchet larger than the denomination of coin being struck, to be fed into the press. For example, a cent could be struck by nickel dies, but a nickel planchet could not be struck by cent dies.
Above: 1981-P Washington quarter wrong planchet error, struck on a Jefferson nickel planchet.
While there are wild, impossible off-metal combinations existing on U.S. coins, they are very rare and almost never offered for sale to the public due to their questionable legality. Examples of impossible error combinations are more common on foreign coins, since various foreign mints, such as those in Malaysia or Bolivia, have lax quality controls. These “impossible” foreign off-metals are completely legal to own in the U.S., and are sometimes offered for sale by error coin dealers. They are quite valuable, and even though they were not created “normally” at the mint, they are still prized by collectors.
Authenticating off-metals is primarily done by checking several of the coin’s characteristics, including the weight, metal, and design of the off-metal. The off-metal should be the correct weight and metal content for the planchet which it is struck on. For example, if the coin being authenticated is a nickel on cent planchet, the coin should weigh correctly for a cent, and should have the correct metal content.
The most common counterfeit off-metals are those struck by false dies, with the planchets being the correct weight and metal content, but the design being fake. In this case, the design and the characteristics of the coin’s surfaces would probably be the only means of diagnosing the coin as counterfeit. This is because counterfeiters will often use a genuine planchet when they mint coins from false dies. Genuine diagnostics to look for on suspect coins include: correct design characteristics; bag marks; everyday damage or wear common to coins found either in circulation or from mint sewn bags; correct finish (if the coin is a business strike, it should have business strike surfaces–not proof surfaces).
Above: 1925 buffalo nickel off-metal struck on a Lincoln cent planchet. A rare off-metal, with around 60 known for the buffalo nickel series.
There are several ways to collect off-metals. Some collectors try to collect a particular off-metal combination by date and mint for a design of coin. If they were building a collection of Lincoln Memorial cents struck on dime planchets, they would try to get an example for every year from 1959-2010, as well as for every mint within those years. This is a very difficult way to collect off-metals due to the inherent rarity of the coins. Such collections are rarely completed, but the challenge is exciting and even achieving an 80-90% complete set is a major accomplishment! Some collectors simply buy a single example of a particular off-metal for their error type sets. However a collector forms his collection, the important thing is that it’s enjoyable and fulfilling.