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- From buell@vectrafitness.com Wed Jan 24 12:28:00 2001
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Date: Wed, 24 Jan 2001 20:15:46 -0000
To: colonial-coins@egroups.com
Subject: Re: Planchet Cutter thoughts
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From: "Buell Ish" <buell@vectrafitness.com>
Dear Kayla, Jim, et. al.:
Your question Kayla is very thought provoking. I think I might know
the answer, but I am not sure to be totally honest. I suspect that
the planchet shows this incised cut only after being flattened by the
coining dies. In other words, I suspect these planchets were far
from flat prior to being coined. I'm going to order some copper
sheet and try this. (I could do it today with steel at hand, but I
presume anything I make would be more interesting and beautiful in
copper.) If I am able to recreate such cutter marks as the 38-c you
posted, the coin Rob Retz posted, the 38-c I bought on ebay (that you
mentioned), as well as those shown on CNL page 789, then I will be
somewhat more sure of my theory.
At this point, I don't know how far to go with this topic. I have
read much of Jim Spilman's 1982 article that he refered me to. There
is a wealth of research here that I plan to spend more time
studying. I would like to thank Jim for bringing this information to
my attention. I had not sought it out. Press operation and die
design is too close to my day job to be my major interest for leisure
time research. Maybe I will get my hands on some copper and that
will change. After my initial study of the material in CNL, I remain
largely of the same opinion as to how many of my NJ copper planchets
were cut out as I offered in my initial posting on this subject. I
have NJ coppers with edge patterns such as those shown on page 792.
Possibly the best of these is a 38-Z. This coin has terrible
surfaces, but possibly no circulation wear. Were Jim to examine this
coin, he and I would likely agree as to how the planchet was cut.
The first third or so of the cut is smooth and straight. Then the
material broke such that there is a granular surface tapering in at a
small angle from the initial cut. This matches exactly the slug
edges that are made by the punch presses I hear every day, all day
from my desk.
I guess I am the diificult pupil. I have a lot of trouble with the
sketches on page 790. I see a very fragile die and punch
arrangement, that would have been hard to make and even harder to run
given the critical alignment required. The negative taper on the
punch would make stripping (extraction of the punch from the copper
strip), a problem. I haven't noticed strippers in any of these
diagrams, fixed or spring loaded. The concave surface on the bottom
of the punch would increase its fagile nature, be hard to create and
sharpen AND not create the metal strip shown directly below it. The
portion of that "metal strip" labeled "Planchet" would be diplaced
downwards. It would not flow up into the descending concave faced
die because there is no pressure to push it into the die. In the
diagram labeled "Normal Rim Burr" Jim is proposing that rather than
the two points shown in the "Metal Strip" meeting, that the strip
broke to the left (or outside) of where the punch's cutting edge was
descending into the material. To me the examples shown on page 795
more or less match the example you posted Kayla. I agree with Jim
that all this is the result of coining planchets with burrs more or
less like those Jim shows on page 790. (my sketches of burr cross
sections prior to coining would be slightly different).
Jim, with all due respect, I respect and admire your research. To be
honest, a small portion of it does not square with my belief model of
the laws of physics. To answer your most authoritative and well
researched paper would require that I make this topic a primary
effort of mine for a lengthy period of time, such as you clearly
did. Given that I have a job, three young children, and other areas
of numismatic research that are at later stages, I am not going to
devote the time necessary. Maybe in the future. When I do, I will
likely find that I agree with more of your article than I do at the
moment. I don't know how to gracefully bow out of this most
interesting of discussions at this point. Clearly this is an
interesting topic to many. Thanks to your article it is possible for
the discussion to occur at a detailed level that would otherwise not
be possible.
My best regards, Buell
PS: Jim, these CNL issues don't come like they used to. I am also
waiting for that mysterious issue #115.
--- In colonial-coins@egroups.com, "kay schlemmer" <kschlemm@m...>
wrote:
> Dear Buell:
> This a very interesting subject. I have trouble understanding how
the
> planchet cutting method you described could result in edges like
the photo
> attached. This 38-c is currently available on ebay. I have a 38-c
in my
> collection which also has this incised partial cut close to the
edge. Also
> I recall you purchased a 38-c recently on ebay which has a partial
incised
> cut through the center of the planchet. All of these planchets
appear to
> have been partly cut then the copper strip moved before another
(this time)
> sucessful cut was made. If the planchet was being pushed by a solid
punch
> why would we get these incised cut marks on the planchet? I would
think the
> inside edge of the partial cut would be raised in comparison to the
outside
> edge, if the planchet was being pushed by a punch through a hole.
I have no
> special knowlege of machinery, but they appear to be made by an
edged
> cutting tool to me.
>
> Kayla
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