SKH-1c-1991-03 Spiked Head

Description

Reported on July 2, 2016, SKH-1c-1991-03 of the 1991 Lincoln Memorial cent offers insight into how die deterioration progresses from initial crack formation toward eventual die failure. A spiked head represents an early-to-intermediate stage in this deterioration timeline: the die has developed a crack significant enough to allow metal flow during striking, but the crack has not yet widened into a full die break or cud that would render the die unusable. In many cases, a spiked head serves as a warning signal that the die is approaching the end of its production life — the same stress fracture that produces the spike will continue to propagate with each subsequent strike, eventually growing into a larger crack, a retained die break, or a complete rim separation. Studying the spiked head census for a given date can therefore illuminate how aggressively the Mint retired deteriorating dies: when many spiked heads are documented (as with the 1991-P cent's 19 varieties), it suggests that dies were kept in service well past the point where cracking became evident, perhaps to meet production quotas or because the spikes were deemed cosmetically acceptable. Struck at Philadelphia on copper-plated zinc planchets composed of 97.5% zinc and 2.5% copper, weighing 2.5 grams and measuring 19mm.

Attribution History

• Discovered by Earl M
• Cross reference: none. 07/02/2016.
• Expert attribution by Cuds on Coins

External References