by Stan McDonald Author
Since the US Mint is producing billions of Lincoln cents every year, the dies used in the stamping process will incur wear and fatigue. Thousands of 2021 Lincoln cents show doubling caused by wear on the dies. The coins are of no added numismatic value, and collectors need to recognize the difference between hub doubling when creating a die and die wear doubling. The most famous doubling caused by die wear is the "poor man's" DDO dated 1955. Not the raised area around the five.
Machine doubling is different from die wear/fatigue doubling. Machine doubling shows a flat duplication of parts of the numbers and letters created from a slight shifting of the planchet in the collar. The collar is the third die since it places the reeded edge on dimes, quarters, and imprints lettering on dollar coins. A typical machine doubled Lincoln cent is shown in the photo of the 1986 Lincoln cent. It is nearly impossible for one number or letter to be doubled since the die is made by pressing a rod into a hub. Although Mint workers did modify dies before 1990 by hand, there are no known single letter or number modifications by Mint workers.
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