RIDB-1c-1972D-01 Retained Interior Die Break

Description

Unlike cuds, which by definition occur at the die rim, RIDB-1c-1972D-01 documents a retained interior die break — a fracture that developed within the interior field or design area of the die, away from the rim entirely, with the broken fragment remaining seated in place. The Cuds on Coins attribution team cataloged this as the first retained interior die break for the 1972-D Lincoln Memorial cent, noting no external cross-reference numbers. Interior die breaks form through similar metallurgical mechanisms as rim cuds — fatigue cracking under repeated striking stress — but their location within the die face rather than at the unsupported rim edge means the fracture must overcome greater structural resistance to propagate. The resulting break typically follows an irregular path dictated by the die steel's grain boundaries, inclusion sites, and residual stresses from the die sinking process. On the struck coin, a retained interior die break appears as a raised irregular shape — sometimes roughly circular or amoeba-like — bounded by a visible crack line, with the interior potentially showing altered relief or surface characteristics where the retained fragment strikes with slightly different pressure or alignment than the surrounding intact die face. Because the fragment is supported on all sides by intact die metal (unlike a rim cud where one edge is unsupported), retained interior die breaks can persist for extended production runs, sometimes producing thousands of coins before the fragment eventually dislodges or the die is retired. This stability means RIDB varieties may be more obtainable than their dramatic appearance suggests, though they remain considerably scarcer than ordinary die cracks.

Attribution History

• Discovered by Chuck Newman
• Expert attribution by Cuds on Coins

External References