CU-1C-1967-04 Cud

Description

Cataloged as CU-1C-1967-04, this fourth cud variety for the 1967 Lincoln cent contributes to a body of evidence about die longevity and failure under the intense production conditions of the late 1960s. The mechanism of cud formation is rooted in the metallurgy of coin dies: working dies are manufactured from hardened tool steel capable of withstanding hundreds of thousands of high-pressure impressions, but each strike introduces microscopic damage at the grain boundaries of the steel. Over time, these micro-cracks coalesce and propagate, particularly at the die rim where the sharp transition from the die cavity to the collar wall creates a geometric stress concentration. When a rim crack reaches critical length, the affected fragment separates catastrophically, often during a normal striking cycle, and every subsequent coin struck by that die carries the cud as evidence of the failure. The 1967 date was the third and final year of the Coinage Act of 1965's mint mark removal, and the year's production of 3,048,667,100 business strike cents at the Philadelphia Mint represented the era's production zenith. An additional 1,863,344 Special Mint Sets were produced at Philadelphia, though cud varieties are almost exclusively found on business strikes, where dies were pushed to their limits rather than carefully monitored. Cross-referenced as CU-1C-1967-04 and attributed by Cuds on Coins. Struck on a 3.11-gram, 19mm planchet of 95% copper and 5% zinc.

Attribution History

• Discovered by Keith Christenson
• CU-1C-1967-04
• Expert attribution by Cuds on Coins

External References