CU-1C-1985-01 Cud

Description

When a hardened steel die endures millions of strikes against copper-plated zinc planchets, the metallurgy of failure becomes inevitable. CU-1C-1985-01 on the 1985 Philadelphia Lincoln Memorial cent documents one such failure — a cud error formed when accumulated fatigue fractures propagated through the die steel until a section at the rim broke free entirely. The resulting void in the die face filled with planchet metal during subsequent strikes, producing a raised, featureless blob at the coin's edge. Die steel used at the Philadelphia Mint in the mid-1980s was typically composed of high-carbon chromium alloy hardened to approximately 58-62 on the Rockwell C scale, a range balancing wear resistance against brittleness. The transition to copper-plated zinc planchets in 1982 altered the stress dynamics — zinc cores deform differently under pressure than solid copper, transmitting force to the die face in patterns that accelerated certain fracture modes. This variety is the first cataloged cud for the 1985 Philadelphia date in the Cuds on Coins registry, establishing the baseline entry for what would become one of the more extensively documented cud populations in the Lincoln cent series. Struck on planchets weighing 2.5 grams and measuring 19mm from Philadelphia's 1985 production of approximately 5.65 billion cents.

Attribution History

• Discovered by David Strzalkowski
• CU-1C-1985-01; number: none
• Expert attribution by Cuds on Coins

External References