SKH-1c-1970D-02 Spiked Head

Description

Second in the spiked head sequence for the 1970-D Lincoln Memorial cent, SKH-1c-1970D-02 records another die crack extending from Lincoln's portrait that produces a spike-like projection on struck coins. Documented on October 13, 2016 — approximately three months after the first spiked head was cataloged for this date — this variety's discovery reflects the systematic examination that variety collectors brought to the 1970-D cent population. Each spiked head variety originates from a different working die, with its own unique crack geometry: the angle of projection, the length of the spike, and its precise origin point on Lincoln's head all serve as diagnostic fingerprints distinguishing one spiked head die from another. No cross-references to other attribution systems have been established. The mechanism producing spiked heads is fundamentally one of die fatigue — repeated striking transfers enormous stress to the highest-relief areas of the die, which on the Lincoln obverse correspond to the hair detail atop the president's head. As the die accumulates strike cycles, microscopic fatigue cracks nucleate at these stress peaks and propagate outward into the lower-stress field area, carving channels that fill with metal during subsequent strikes. The resulting spike may grow longer as the crack extends with continued die use, meaning later die states often show more dramatic spikes than early states from the same die.

Attribution History

• Discovered by JC Stevens
• Cross reference: none. 10/13/2016
• Expert attribution by Cuds on Coins

External References