Doubled Die Coins
A doubled die coin is a coin that was struck from a coin die that had a partial or full doubled image on it. The doubling comes from mistakes in the die hubbing process, where more than one image is transferred from the hub to the coin die. The 1955 doubled die Lincoln Cent (see photo) is the classic example of a doubled die, and sparked the start of the error coin collecting hobby in the U.S. Although no other doubled die types exhibiting the remarkable degree of doubling seen on the 1955 cent have emerged from the U.S. Mint, noteworthy doubling has also been found on 1972 and 1995 Lincoln Cents.
Not Double Struck
Many people mistake double struck coins for doubled die coins. The key difference between the two is that double struck coins are struck while the coin is in the coining chamber of the coin 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.
Doubled die coins are manufactured from coin dies that were not properly made. As indicated above, it takes several impressions from the coin hub to make a coin die. If the mint employee does not align the hub perfectly above the coin die, a second impression will result on 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 designate if the coin is doubled die on the obverse or the reverse.
Some doubling effect is so minute that it requires a loupe or microscope to see it. When cataloging coins coin collectors and numismatist will designate Double Die Obverse with the letters "DDO". Double Die Reverse coins will carry the "DDR" designation.
Tripled, Quadrupled and More
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 coin hub is not precisely aligned in two or more of these impressions, it is possible to produce a Tripled Die or a Quadrupled Die. These designated as follows:
- TDO: Tripled Die Obverse
- TDR: Tripled Die Reverse
- QDO: Quadrupled Die Obverse
- QDR: Quadrupled Die Reverse
Beware of Chinese Counterfeits
Some of the more valuable doubled die coins (1955 and 1972 Lincoln pennies) are being manufactured by Chinese counterfeiters. Before you buy one of these high-priced coins you should make sure that you are buying it from a reputable coin dealer or that it has been certified by a third party grading service.
Mechanical Doubling and Die Abrasion Doubling
"I check every single coin that comes into my hands to see if it is a doubled die minting variety."
Edited by James Bucki