2006-P Jefferson W/Crack

Rackster,

When I purchased that Bush (the elder) Shattered Die it was missing three pieces from the base so you'd have a heck of a time putting that one together!

When they send my engraver a die to make over, they only worry about sending all the pieces to fit the face of the die.

Here is a die pair with virtually identical breaks on the foot of the dies. A metallurgist that I met at a coin show looked at these and explained the breakage and the term used for where I placed the arrows but I misplaced my notes and never got a chance to figure out what he was talking about other than the fact that each die is machined from one piece of die steel. They almost appear to be two-piece; the foot and the body. Anyway, looking at these makes one wonder what the coins looked like that were struck with them in this condition.

Rackster,

These are Columbia style dies that had perfectly round bases that broke almost identically on each. They were St. Gaudens style dies for 1oz rounds. There were no flats. Flats on this style die are not all that common though I have seen them.


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 then your balance would get shifted to one side.



Below are the images of the broken set of dies.











Note the Beach Marks. This represent repeated loads on the failing die. The area outside this zone is where the rest of the foot sheared away at the time of "Final Fracture."
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.

Thanks Dar - it earned a 2x2 flip!

Ken - beach marks appear to be a fitting label. The break looks like out going tide marks.

nice find