The Variety Coin Register®
Copyright Ken Potter 2001
1963-D 50c Doubled Die Obverse
The photos below show the strongest areas of doubling on the date and LIBERTY on this Franklin Half dollar. Listed for James Moloney in September of 1999 as VCR#1/DDO#1.
Hub doubling, or what collectors commonly
refer to as a doubled die, is possible due to a phenomenon known as work hardening. This
causes the metal of the face of a die to become too hard and too brittle to allow a
complete image to be sunk into the die in one operation without causing it to crack or
shatter (during the multiple hubbing process). As a result, several impressions or
hubbings are required to produce a die when using this process. (The multiple hubbing
process was largly replaced by the U.S. Mint starting in 1997 and 1998 by the more modern
"single squeeze" restrained hubbing process.) Between each hubbing the die
is removed from the press and annealed (softened) thus allowing for another impression
without shattering the die. If for some reason a partially finished die is reinstalled
into a press for strengthening and the hub and die are improperly indexed, resulting in a
misalignment of images, or if the hub varies in design from the one(s) used for earlier
impressions -- hub doubling will result.
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