9462Re: Unusual upset on a nickel planchet
- Sep 7, 2005One thing I'd like to understand about planchets such as the one you
pulled out is exactly how such a wide, high proto-rim is produced. It
would seem that more than simple squeezing and rolling is involved. It
looks almost as if the two faces are clamped between two flat cylinders
as a slightly wider perimeter is squeezed and rolled. Otherwise, does
one explain the abrupt junction between inner border of the proto-rim
and the flat surface?
Does anyone out there have a clue?
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