PART VI. Striking Errors:
Abnormally Strong Strike:
Due to Stacked Coins or Planchets
Definition: Effective striking pressure is always increased when the aggregate thickness between the dies is increased. An extra planchet or coin inserted into the striking chamber will cause a significant increase in effective striking pressure. If one or both coins are struck within the collar, those coins confined by the collar will show strong finning. Finning occurs when coin metal squeezes into the narrow gap between die neck and collar. If one or both coins are struck outside the collar, they will expand enormously.
This 1998(P) Lincoln cent was stuck twice, with a 95% indent on the second strike. The first strike was a normal strike that failed to eject from the striking chamber. The second strike occurred with a planchet on top of the newly-struck coin. Neither coin was confined by the collar during the second strike. As a result, both coins were broadstruck. The bottom coin, pictured above, expanded to the size of a quarter dollar. The reason AMERICA is noticeably doubled is that this part of the coin was pushed beyond the limits of the striking chamber as the bottom coin expanded from the pressure of the two stacked discs. Other doubled design elements include the G of FG (the designer’s initials), the C of CENT and the O of ONE.