NNP

Wrong Planchet.  An unintended striking on a planchet of wrong size, shape or composition. Most serious is a wrong planchet of incorrect composition, also known as off metal (abbreviated omc for off metal composition). Such a wrong planchet strike exhibits an incorrect color. A blank that is too small and some of the lettering or design is not in the struck portion is called off flan.

What may appear as a wrong planchet, a medallic piece that mis-states the composition on the edge lettering, is not usually a wrong metal – it is an error of edge lettering (for example, an obvious bronze medal marked silver is not an off metal or wrong planchet, but an error of edge lettering).

excerpted with permission from

An Encyclopedia of Coin and Medal Technology

For Artists, Makers, Collectors and Curators

COMPILED AND WRITTEN BY D. WAYNE JOHNSON

Roger W. Burdette, Editor