Part VI. Die Errors:

Collar Breaks (Collar Cuds):

Catastrophic collar failure

Definition: A collar’s brittle failure captured in time by a coin struck during the crack-up.

Since collars fail far less often than dies do, it’s no wonder that the catastrophic failure of a collar is almost never documented by a coin struck at the moment of failure.

This 1964 5-cent proof mated pair records the breakup of the collar on the second strike. A 5-cent planchet was struck normally and attached itself to the hammer die. A second planchet was fed in beneath it and the two coins were struck together within the collar. The increased effective striking pressure generated by the two stacked discs proved too much for the collar, which split apart at five points.