July 2003 Book Review Part Two
Special *July 2003* Early Addition Of Our Book Review:
Indepth Book Review On 2000 North American Coins & Prices:
A Guide To U.S., Canadian and Mexican Coins....
Collectible Treasures Antique and Collectibles
Book Review July 2003
Interesting Information On Coin Collecting as noted in the 2000
North American Coins & Prices: A Guide To U.S., Canadian and
How coins are manufactured: by Alan Herbert
Just as printing is the process by which paper money is made, so
is minting the method of manufacturing coins. The two are often
confused by the public, but they are completely different.
The history of minting goes back several centuries before the birth
of Christ. The Lydians are credited with making the first crude coins
in the Middle East about 700 B.C., although the Chinese and Koreans
trace their coinage back even further.
Some early coins were cast. That process continued in China into
the 1900s, but only for low-value pieces. Here again the average
person often assumes that all coins are cast, but as you will see,
only a tiny fraction of a percent are--or were--actually made that way.
The methods developed by the Greeks and Romans centered on
making dies that could be hammered by hand into the surface of a
lump of metal, flattening it and impressing a design. Hammered
coinage continued until after the end of the Middle Ages, about 1500.
After that the first machines that could strike coins were invented.
Today their successors can pound out 750 or more coins a minute.
From the early days when the fixed die was driven into a stump or a
hole drilled in a rock, through fixing it in an anvil (the fixed die is still
called the anvil die), to today's modern coin presses, the process is
much the same. Force is applied to devices that impress or apply a
design to a piece of material, which is transformed into a coin.
Early dies were made of wood. Then came copper, bronze, and finally
iron as technology advanced. Today dies are made from exotic steels
with special qualities that make them ideal for striking coins.
The history of coinage is fascinating. Interwoven into it are several
familiar names: Leonardo da Vinci is credited with inventing one of the
coin presses. James Watt, English inventor of the steam engine, was
the first to incorporate steam power to drive the coin presses that earlier
had depended on horses or human arms.
Whether the power comes from a hand holding a hammer or a
mechanical ram, and whether it comes from above, below, or the
side, the process is called "striking" a coin. Modern coin presses
use a variety of methods in applying brute force to a piece of metal to
turn it into a coin.
Another fable that traces to casting coins is the common belief that
coins are made from liquid metal or at the least are red hot when they
are struck. Neither is true. A coin's design is formed by the pressure
that causes the metal to cold-flow into the pattern that you see on the
coins in your pocket.
There are three basic parts of the minting process: (1) the making of
the planchet, which is divided into the selection and processing of the
metal and the preparation of the planchets, (2) the making of the dies,
and (3) the use of the dies to strike the planchets. To help you
remember these three parts, think of "P", "D", and "S" for planchet,
die and striking.
CHOOSING A METAL
Many different metals have and are being used for coins. The most
popular coinage metals are those commonly found and relatively
cheap, so they can be used for striking low-value coins. Precious
metals--like silver, gold and platinum--are still used for commemorative coins.
A good coinage metal requires certain properties. The metal must be
soft enough to be easily worked yet hard enough to withstand the wear
and tear of a thousand pockets, a hundred thousand transactions. Few metals have all the right properties, so coin metals usually are an alloy,
or mixture of two or more metals.
Copper is a favorite coin metal, either by itself or in an alloy. Zinc,
nickel, iron, and aluminum are also found in coins struck by the United States and other countries. Silver and gold have to be alloyed with
some metal, usually copper, to be hard enough to withstand commercial life. The so-called "pure" coins of silver or gold are known as "bullion
coins," bought and sold primarily for their precious-metal content.
The metals chosen for a coin are melted and mixed together, and
either poured into ingots or blocks, or extruded from furnaces that continuously cast a long strip of the metal. The ingots are passed
several times between the big rolls in a rolling mill to reduce the ingot
to the thickness of the blanks needed.
Once the strip is rolled to the correct thickness, it is sent to a
blanking press. A gang of blunt-end punches are driven through the
sheet, producing a dozen or more blanks with each stroke. The rough blanks are then ready to be processed.
PREPARING THE DIES
For those who haven't studied metallurgy, the concept of hard metal
flowing about is pretty hard to swallow, but this is actually what
happens. It is basically the same process as the one used in an auto
plant to turn a flat sheet of steel into a fender with multiple curves and
sharp bends. The cold metal is moved about by the pressure applied.
To make the metal move into the desired design, there has to be a die. Actually there has to be two dies, because one of the laws of physics
is that for every action there has to be an equal and opposite reaction.
You cannot hold a piece of metal in midair and strike one side of it.
Instead you make two dies, fix one, and drive the other one against it--
with a piece of metal in between to accept the design form each die.
A die is a piece of hard metal, like steel, with a design on its face that
helps to form a mirror image on the struck coin. Early dies were made
by hand. Engravers used hand tools to laboriously cut each letter,
each digit, and each owl or eagle or or whatever design was being used
into the face of the die. Notice that this is "into" the surface of the die.
Each part of the die design is a hole or cavity of varying shape and
This is because we want a mirror image on the coin, but we want it
raised, or in "relief." To make a relief image on a coin, the image on
the die has to be into the face of the die, or "incuse." Of course, if we
want an incuse image on the coin, such as the gold $2.50 and $5
coins of 1908-1929, the design on the die face would have to be in
To fully understand this, take a coin from your pocket and a piece of aluminum foil. Press the foil down over the coin design and rub it with
an eraser. When you take the foil off and look at the side that was in contact with the coin, you have a perfect copy of a die. Everywhere
there is a relief on the coin there is an incuse design on your foil "die."
FROM SKETCHBOOK TO COIN
The design process begins with an artist's sketch. This is translated
into a three-dimensional relief design that is hand-carved from plaster
or, in recent years, from a form of plastic.
The plaster or plastic design is then transformed into a "galvano," which
is an exact copy of the design that has been plated with a thin layer of copper. This is used as a template or pattern in a reducing lathe, which
cuts the design into a die blank.
This die becomes the master die, from which all of the following steps descend. The process can be reversed so that the design will be cut
in relief, forming a tool called a "hub," which is simply a piece of steel
with the design in relief, exactly the same as the relief design on the intended coin.
of July 2003 Book Review
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