Blanks, planchets, and coins must travel through a gauntlet of moving parts capable of inflicting damage. Traumatized coins may end up scraped, gouged, dented, pinched, torn, twisted, bent, sheared, crumpled, or crushed. Identifying the particular step of the minting process during which damage is inflicted is important from both a diagnostic and commercial standpoint. Damage that occurs after the strike generally has no value.
For those coins with collector value, a broad diagnosis of pre-strike damage may be the only option when evidence is limited. However, it’s sometimes possible to be more precise.
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We start with a 1998-D Washington quarter dollar that was struck on a planchet whose upper right quadrant was pinched off, with the clad layers pinched together to hide the copper core. At the opposite pole a weak design rim ends abruptly at an edge that is unusually well-struck with strong reeding. This “Blakesley effect” tells us that the blank was damaged before it entered the upset mill. The missing metal prevented the opposite pole from being rolled and squeezed in the horizontal plane, leaving the planchet with a bulging edge with no adjacent proto-rim.
Our next example is an off-center copper-plated zinc cent struck on a planchet that had large areas of copper plating scraped off before the strike on both faces.
Far less common is damage that occurs before plating. Such is the case with a 1987 Lincoln cent struck on a planchet with a struck-in rim burr. Had this fang-like spur been torn up after plating, the zinc core would have been exposed. Instead, the plating is undisturbed.
Inter-strike damage (damage that occurs between strikes) is visible in a 1985-P Jefferson 5-cent coin with a flipover double strike. Both faces were deeply gouged in the same area after the first strike. Since each strike was delivered by a different die pair, this also probably represents a delayed second strike.
Intra-strike damage (damage that occurs during a strike) is a phenomenon restricted to off-center strikes and affects the area that protrudes outside the striking chamber. It is not caused directly or indirectly by the dies or any object trapped between the dies. Intra-strike damage sometimes occurs when metal expanding beneath the dies pushes the rest of the coin sideways into a waiting obstruction. It can also occur when the protruding portion of an off-center coin is damaged by a moving part while the coin is pinned between the dies. The left side of the illustrated off-center Roosevelt dime was pushed in by a machine part (probably an ejector) as the right side was trapped between the dies. As is often the case with such errors, radial expansion of the right side was impeded by a second machine part (undoubtedly a feeder) that was also caught between the dies.
Post-strike damage is generally valueless, as it can easily be duplicated outside the Mint (either intentionally or accidentally). Retrieved from a Mint-sewn bag, this 1995 Lincoln cent was damaged after the strike, when it was crushed against several other cents.