9464Re: Unusual upset on a nickel planchet
- Sep 7, 2005Another implication.
A planchet such as yours or one like my off-center nickel features a
proto rim that is considerably wider than the design rim. The proto-
rim would therefore intrude into the area struck by the field portion
of the die. The result might be the creation of two circular
fissures, one on each face. That's because the inner portion of the
proto-rim would be flattened out by the force of the strike and
the "extra" metal driven into the rest of the planchet.
There is a dime-thickness 1971-D nickel struck on a seemingly clad
(and certainly composite) Cu-Ni/Cu planchet that features these two
circular fissures. There are some undersized and underweight clad
quarters and a Tennessee quarter struck on a clad dime planchet that
show the predicted fissures. Could these have been struck on such
peculiarly upset planchets? It's possible
> No clue at all, it is just strange.
> --- Mike Diamond <mdia1@a...> wrote:
> > One 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?
- << Previous post in topic Next post in topic >>