RIDB-1c-1964-01 Cud

Description

Classified under the "Cud" error type despite carrying the RIDB (Retained Interior Die Break) prefix in its catalog designation, this RIDB-1c-1964-01 is a 1964 proof Lincoln cent variety that documents progressive die deterioration on Lincoln's forehead. The comments note die cracks on the forehead indicated by "white arrows" in the reference photographs, describing a network of fracture lines in the die steel that manifested as raised lines on the struck coin's surface. Die cracks form when the immense pressures of the striking process create stress fractures in the hardened die steel, and on proof dies — which operate under even higher striking pressures than business strike dies to achieve the full metal flow needed for mirror surfaces and frosted devices — these fractures can develop even within the die's relatively short service life of approximately 3,000 impressions. The presence of forehead die cracks on a proof die suggests either that this die was approaching the end of its useful life or that a structural weakness in the die steel accelerated the fracture process. Despite the RIDB prefix in the catalog number, the error type classification as "Cud" reflects the cataloging conventions used during the original data import. A companion listing under the same RIDB-1c-1964-01 designation exists with the "Retained Interior Die Break" error type classification, representing a different strike type. Cross-referenced with date 04/15/2019 and attributed by Cuds on Coins. Struck from the 1964 proof mintage of 3,950,762 cents on a polished 3.11-gram, 19mm bronze planchet of 95% copper and 5% tin-zinc.

Attribution History

• Discovered by Pete Apple
• Cross reference number: none. 04/15/2019.
• Expert attribution by Cuds on Coins

External References