Coin dealers are always getting asked “what is my double stamped coin, penny, nickel, etc… worth?”. When the question should be what exactly is a double stamped coin and could the coin I have be one? Double stamped coins are more properly known as multiple stuck coins. These are error coins that have for a number of technical reasons received more than one or impression from the die. Often miss-aligned and many times dramatic. If the doubling is slight the collector value will be minimal or it maybe an example of “step-doubling” or “machine doubling” or “mechanical doubling”.
Mechanical Doubling
Is a when a coin exhibits a minor low relief design element to slightly to one side and frequently higher or lower than the element it is imitating. This form of “doubling” is caused by looseness in the coin press mechanisms. This play allows die movement during the striking process. It allows the die to twist and drag against the planchet or face of the coin. This is not a design error, nor is it considered a mint error. This form of coin doubling does not add any extra collector value.
Doubled Die Coins
As the term suggest, are produced from a doubling of the design elements from the die itself. When the U.S. Mint makes a die used to strike the planchet that is the raw form of a coin, it uses a working hub to impress the image into the die. This impression of the die takes several attempts to fully transfer the image. It is during this process that a real double die coin can be produced.
Error coins
Are mistakes that occur during the process of striking a coin. A true error coin is usually in relatively new to uncirculated condition. This is because an error coin does not circulated very long. It is usually noticed by someone early on in its use and therefore “save” it.
Most modern double stamped or multiple strike error coins are rather common and have minimal extra collector value. Usually under $100.00 with many rather dramatic examples to be had for only a few dollars.
For a deeper dive into the subject of Error Coins and Variety Coins select here.