Mints and Minting
How Coins Are Made
Coins are struck from dies, which are two cylindrical pieces of metal, each bearing an incised design, date, and other information. These dies are mounted in a coining press. A blank disk, called a planchet, is inserted on top of the lower die, the top die is then squeezed or forced against the planchet with many tons of pressure, and a coin is created.
As the metal is squeezed by the dies, it flows outward into a collar or retaining device. Certain retaining devices have ornamentation such as vertical stripes, called reeding. In early years of the mint, the blank planchets themselves were put through a special lettering machine before the planchets were struck, and on the edge of the planchet was inscribed lettering such as FIFTY CENTS OR HALF A DOLLAR. Such pieces are known as "lettered edge" coins. Certain later coins, the $20 pieces of 1907-1933 for example, had the lettering, such as E PLURIBUS UNUM, applied by the collar.
The entire minting process involves refining metal to the correct proportion, rolling it into strips, cutting planchets from it, striking the coins, sorting and bagging them, and distributing them into the channels of banking and commerce.
In the early days dies were cut by hand. By means of an engraving tool the die cutter would create the figure of Miss Liberty, an eagle, or other motif. Letters and numerals would be added to the die individually by means of punches. Certain other punches were used for elements as leaves and berries. Each die was slightly different from all others. The collecting of coins made by different dies is a fascinating pursuit. Sometimes a die would last long enough to make tens of thousands of coins before it broke, and thus coins from such a die are easy to find today. In other instances a die would break shortly after it was first used, only a few pieces would be struck from it, and today that particular die variety is rare.
Beginning about the year 1836 the preparation of dies was mechanized, and the lettering, eagle, figure of Miss Liberty, and everything else but the date was stamped on the die from a master die or hub. The date figures were then added individually. Soon thereafter, logotypes consisting of an entire date, such as 1898, were made, and the date was then punched in all at once, rather than individual date punches. Still later, the date was included in the master die, and all working dies were stamped with all information on them -including the date, design, and lettering. That is the way dies are produced today. Consequently, there are relatively few die variety differences among modern coins.
PCGS Coin Guide Table Of Contents
