24722Three impressive examples of "slide doubling"
- Nov 2, 2011Slide doubling is a form of machine doubling that occurs when a die shifts sideways after reaching the lowest point of its downstroke. In doing so it smears the design.
Severe examples are rare, but in recent weeks eBay has provided three exceptional specimens:
In each case the die obverse die landed in a misaligned position and then scraped its way back toward the center. In the case of the 1996-D quarter, the die actually touched down in a centered position, jogged to the right as it completed its downstroke, and lurched to the left creating the machine doubling. I have a second quarter struck by the same die pair that shows the same pattern, and I've seen a third. The "damage" along the right margin appears to represent damage to the coin generated during the strike by burrs or irregular damage present on the edge of the die. I suspect the "damage" on the two nickels was also generated during the strike, but I don't have them in hand yet to verify this suspicion.
Since the quarter moved to the right during its downstroke (leaving a featureless crescent marked by fine parallel striations) it would necessarily have erased any lightly-impressed design elements it generated during initial touchdown. It would therefore represent a "design ablation" error. I suspect at least one of the nickels shows a similar design ablation error.
Even though their misalignments are in opposite directions, I'm hoping the two 1999-D nickels were struck by the same die pair. I'll report back.
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