I was relating the information provided by the Philadelphia Mint in educational program
describing the coining process by following it through the mint. After the coin is
designed and created in plaster? about the size of a large, round dinner platter, it's
taken to an ancient machine made in the late 1700's where it slowly spins with a large,
vertically oriented platter. A follower pin like device follows the contours of the
design
like playing a vinyl record and the machine mechanically cuts a replica at the proper
size. This replica is used to make an inverse relief of the coin which is then used to
make 10 or so proper reliefs which are each then used in turn to make a number of dies.
When a die is first mounted to the stamping machine, a very short run is made (the
stamping is incredibly fast, the pressure is very high and varies with the size of the
coin. The Sakajowea(sp) dollar requires 50,000 lbs to stamp). The coins from the short
run
are examined for their degree of perfection. If bad, the die is tossed and a new die is
installed and another test made. These are the first coins produced from a die and are
of
the highest quality that the particular die set will produce. They are exceedingly
rare in
comparison with the total number of coins stamped. These are the proof coins because
they
prove that the die set is stamping correctly and is likely to produce many coins.
Quality
is downhill from there for that die set because they wear. From then on, the coins are
sampled to monitor the condition of the dies and when the coins degrade to much,
another
die set is installed and more proof coins are produced.
Double striking, etc. is a whole 'nother category. These coins are produced solely for
collectors. Of course, proofs are made of these as well before the (usually very
limited)
run is made, so proofs of these are made available at an even higher price.
Regards,
Bob...
From: "Daniel J. Matyola" <[EMAIL PROTECTED]>
> Bob Blakely wrote:
>
> > >From coin minting and collection...
> > Proof means the first coins struck from a particular die set and examined by
> > mint personnel for sufficient perfection to continue stamping with that
> > particular die set.
>
> Not quite true. Proof coins generally are struck from special dies, at higher
> pressure, and with multiple strikes, to make a coin with better detail and more
> luster. The rest of your description of coin grades is, AFAIK, accurate.
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