Interesting Center Die Cracks On 1990 LMC

Iwannado, yea, see a lot of die cracks that come off the four corners of the Memorial. Was just sitting here thinking about that...wonder metallurgically(?) if there are weak or stressed points inherent in the dies themselves. Where the central design element, (in this case the Memorial) being close to the edge of the die, that corner after being squeezed into the die cavity causes a weakness there, later to start splitting. This same scenario is on the obverse on the "Spiked Head" die crack. Anyone with a degree in metallurgy?

See below for a link to a Masters thesis by Derya Akkus titled ANALYSIS OF COINING PROCESS IN PRODUCTION OF
MEDALLION

There is an interesting numerical simulation of the stress concentration for various parts of the minting process including creating blanks and striking. See, for example, Figures 5.7 and 7.18, which tend to support my response above. While it clearly is way more complicated than I first described (e.g. Figure 7.9), I still think that sharp corners at the periphery are likely starting points for a die crack.

http://etd.lib.metu.edu.tr/upload/1...47/index.pdf

Yes. Two common examples of points of inherent weakness in the die design are cracks emanating from all four corners of the Lincoln Memorial and the leading wing edges and base of the bust on Washington quarters. You will see die cracks formed in those areas on coins from a wide swath of years and mintmarks.