Many people confused double die coins with double struck coins. The major difference is that double struck coins are struck twice by the same coin die during the striking process. A doubled die coin is produced when the coin die is not properly manufactured. This leads to the appearance of two images on a single coin die. The more obvious and distinct the error is, the more the coin will be worth.
撞击双模硬币的硬币模具具有部分或完全加倍的图像。因此，硬币有两个相同的图像略微偏移。从死亡中的错误发生了加倍hubbing process。This results in a coin die having more than one image on it.
1955 doubled die林肯美分（见图）是双重模具的经典示例。这些双死的硬币引发了开始的开始错误硬币collecting hobby in the United States. Although no other doubled die types exhibiting the remarkable degree of doubling seen on the 1955 Lincoln cent, other cents have emerged from the U.S. Mint. Other noteworthy doubled die coins are the 1972 and 1995 Lincoln Cents.
Not Double Struck
Many people mistake双击coins对于一倍的模具硬币。关键差异是双击coins are struck more than once while the coin is in the coining chamber of the coining press. When this happens, the first impression is flattened, or sometimes obliterated by the second strike. Subsequent strikes will also flatten or obliterate the design from earlier strikes.
Coin dies that are not appropriately made result in doubled die coins. As indicated above, it takes several impressions from the coin hub to make a coin die. If the mint employee does not align the coin hub perfectly above the coin die, a second impression will result in the coin die that is slightly off-center from the first. If this coin die is used to make coins, all coins made from the die will have this doubling effect.
Doubled Die Designations
Coin collectors and numismatists will examine the coin indicating if the doubling on the obverse or the reverse. Some doubling effect is so minute that it requires a寸镜头或者显微镜看见了。当编目硬币时，硬币收藏家和数字主义者将指定Double Die Obversewith the letters "DDO."Double Die Reverse硬币将携带“DDR”名称。
Since the manufacturing process to produce a coin die involves multiple impressions from the coin hub, it is possible that more than two impressions may be needed. If the mint worker does not precisely align the coin hub with the coin die, it is possible to produce a三倍的死亡或者aQuadrupled Die。这些被指定如下：
Beware of Chinese Counterfeits and Machine Doubled Coins
Chinese counterfeitersare manufacturing some of the more valuable doubled die coins (1955 and 1972 Lincoln pennies). These are high-quality coins made by counterfeit manufacturers in China. Unfortunately, it is not against the law in China to make "reproductions" of United States coins. Therefore, before you buy one of these high-priced coins, you should make sure that you are buying it from a reputable coin dealer or purchase a coin certified by a第三方等级服务。
The proper numismatic term is "doubled die." Sometimes people refer to these as "double die." Although this is incorrect, most coin dealers will know that you are referring to doubled die coins.
Edited byJames Bucki