Part VI. Striking Errors

Machine Doubling

Rotational Machine Doubling

Definition: Machine doubling that occurs when a die rotates after reaching maximum depth of penetration into the coin.  It can occur on either face or both faces simultaneously.  It can manifest either as push doubling or slide doubling.

This 1996-P nickel shows rotational machine doubling on both faces in the same direction.  It conforms to the push doubling subtype, as marginal shelving is well developed.  Since the direction and distance of the displacement is the same on both faces, there’s a good chance that it was the newly-struck coin that rotated, instead of the dies.  This could have been accomplished by by a rotating collar.

For more information, see this article: http://www.coinworld.com/news/us-coins/2015/07/when-machine-doubling-is-doubled–collectors–clearinghouse.html