Planchet crack with odd edges leads to Type III stutter strike

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Published : 08/17/13
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Regular readers of this column may recall two previous articles dedicated to stutter strikes (Dec. 28, 2009; July 25, 2011).

Arising under disparate conditions, stutter strikes are generated by brief, early die contact and appear as an outlying crescent of die-struck design that is restricted to one face. The continuation of the hammer die’s downstroke generates the definitive strike, which lies medial to the stutter strike.

Three types of stutter strikes have been defined. All are rare, with Type III being the rarest. I had assumed that the hammer die would generate the crescent of die-struck design in all three types. That assumption has now turned out to be too restrictive, at least with respect to Type III stutter strikes.

My assumption was falsified by an off-center dime that was recently sent to me by Matt Dinger, owner of Lost Dutchman Rare Coins in Indianapolis (www.ldrcoins.com). It displays a Type III stutter strike on the reverse face, which was struck by the anvil die. The outer edge of the struck tongue of metal also features a chain strike. When struck, this planchet lay right next to a second planchet. The two expanding edges collided with each other, producing a common straight edge.

A Type III stutter strike depends on the presence of planchet or coin that is bent, crumpled or that assumes some other complex three-dimensional shape. The distortion can occur before, during, or between strikes. The distorted disc proves unstable on a flat surface, with a tendency to rock and slip when subjected to the touch of a die. If a point of initial contact between the die and the distorted disc lies near the edge of the die face, the affected area can slip sideways and out of the striking chamber before the downstroke is completed.

I had always imagined that the highest point on the upper surface of the unstable mass would be the area most likely to end up with stutter strike. But on further consideration (prompted by this new example) there’s no reason why a point of contact with the anvil die couldn’t potentially receive a stutter strike as well. After all, the base of the distorted disc would rest on the anvil die, supported at two or more points. If one of those points happens to lie near the edge of the anvil die, it could be pushed sideways and out of the striking chamber in the course of the downstroke.

The dime planchet that received the off-center strike arrived in the striking chamber with a long crack that presently shows complementary beveled edges. Although the crack lies along the inner margin of the definitive strike, it was clearly not caused by tensile stresses generated during the strike. The obverse copper-nickel clad layer has been smeared over the medial edge of the crack while the reverse clad layer has been smeared over the lateral edge of the crack. A tear caused by tensile stresses wouldn’t show any smearing of the clad layers.

The crack and the smeared cladding could have been created simultaneously by mechanical damage prior to the strike. However, I think it’s more likely that the crack formed well before the strike, while the smearing of the clad layers (and perhaps the bevel) occurred during the strike. This scenario makes perfect sense if we assume that the planchet was horizontally compressed after the crack developed. This compressional damage caused the edges of the crack to telescope, with the lateral edge riding over the medial edge. This overlap would also have been key to the formation of the stutter strike.

Telescoping such as I’ve described is displayed in an off-center 1974 Mexico 20-centavo coin, illustrated this week. The facing edges of a long fissure overlap in the unstruck crescent.

During the strike that produced the off-center dime, the die margins more-or-less coincided with the telescoped edges of the crack. When the hammer die made initial contact with the uplifted lateral edge, the undershot medial edge simultaneously picked up partial reverse lettering (ONE). As striking pressure increased, the medial edge was forced out from beneath the overhanging lateral edge and beyond the striking chamber. The smearing of the clad layers occurred at this point. The lateral side of the crack remained within the striking chamber; any design left on its upper surface by initial die contact was wiped out by the completion of the hammer die’s downstroke. The completion of the definitive strike left the two sides of the crack aligned in the horizontal plane.

Additional supporting evidence for a single-strike scenario can be found in the positioning of the outlying extra letters; these lie opposite the slide zone of the obverse strike, rather than the obverse design proper. There are also no signs of an earlier strike beneath the definitive strike.

Coin World’s Collectors’ Clearinghouse department does not accept coins or other items for examination without prior permission from News Editor William T. Gibbs. Materials sent to Clearinghouse without prior permission will be returned unexamined. Please address all Clearinghouse inquiries to cweditor@coinworld.com or to 800-673-8311, Ext. 172.

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