Set Of St.gaudens 1oz Ag Dies With Broken Bases Dissected

At the end of an earlier thread that I believe is going stale, I posted the following that is better suited to a new thread:

These are Columbia style dies that had perfectly round bases that broke almost identically on each. They were Saint Gaudens design dies for 1oz rounds. There were no flats. Flats on this style die are not all that common though I have seen them. Columbia style dies are pretty much the standard used by the majority of mints.


The breaks were due to localized fatigue overload at the edges. I'd guess there may have been a shift in the balance possibly due to faulty die holder set up. Shown here is a 4-post die set up that the company that produces my die blocks and hubs makes. If one or two of the posts went out on one side then your balance would shift to one side. Of course the cause may have been something completely different.



Below are the images of the broken set of dies.











Note the Beach Marks. They represent repeated loads on the failing dies (they are easiest seen on the die to the left). The area outside this zone is where the rest of the foot sheared away at the time of "Final Fracture."
I also point out Ratchet Marks. You can read about Ratcheting Marks here:
http://www.asminternational.org/ema...6605p039.pdf. There is more here than I care to pretend that I fully understand.

There is a ton on the Internet about metal fatigue and its effects.