CU-1C-1991-04 Rim Cud

Description

Closing the four-variety cud census for the 1991 Lincoln Memorial cent, CU-1C-1991-04 is specifically designated as a rim cud — a classification confirming that the die break occurred at the outermost edge of the die where it meets the collar. Rim cuds are the most common cud configuration because the die rim is a structural weak point: it forms a thin wall of steel at the die's perimeter that absorbs repeated high-pressure impacts without the reinforcement that the collar provides to the die face interior. Over millions of strikes, thermal expansion and contraction cycles combined with impact stress concentrate fractures at this vulnerable boundary, eventually causing a section of rim steel to shear away. The distinction between a rim cud and an interior die break is important for classification: rim cuds always connect to the coin's edge and produce a raised area that extends from the rim inward, while interior die breaks create isolated raised masses entirely within the design field. As the fourth and final cud cataloged for 1991, this variety completes a quartet of die failures that collectively illustrate the mechanical limits of die steel under sustained production demands at the Philadelphia Mint. Struck at Philadelphia on copper-plated zinc planchets composed of 97.5% zinc and 2.5% copper, weighing 2.5 grams and measuring 19mm.

Attribution History

• Discovered by Earl M
• CU-1C-1991-04
• Expert attribution by Cuds on Coins

External References