Livin' on the edge
U.S. uses lettering on coins' 'third side' since beginning
posted 4/25/06
By Jeff Starck
Coin World Staff
The
Presidential dollars program, which begins in 2007, will not only herald the debut of such luminaries as Franklin Pierce and James Buchanan to U.S. coinage, but is significant for something many citizens may not notice - lettering on the edge.
Every coin has three sides, though few people think of a coin as a three-sided object. But the edge of the coin often tells the most interesting story and is ripe for rediscovery.
Edge lettering (and other devices like reeding) were a practical answer to an age-old problem: coin clipping. Before minters began marking the edge with distinctive designs, it was easy and profitable to clip or shave small pieces of metal from silver and gold coins. Since the coins in those days were worth their weight in the metal of which they were struck, they could be devalued or made worthless if too much of their metal was whittled away.
Giving a silver or gold coin an edge design made it harder for criminals to remove metal from the edge the coin and later pass it as containing its full measure of metal.
A "clip" is the accurate way to refer to a coin that has been damaged and forever marred by the removal of its metal. (An "incomplete planchet" error is the term that applies to coins created by the Mint that are not round, complete or otherwise whole when struck. Error collectors are aware that "clipped planchet" is the most common name for this error, though "incomplete planchet" is a more accurate description.)
As early as 1658, the English government under Oliver Cromwell issued crown and half-crown coins with raised edge lettering, a practice to continue through the reign of George IV.
The first use of edge lettering on a U.S. coin was on one of the first coins, the 1793 Liberty Cap
Half Cent. The edge is lettered, and states TWO HUNDRED FOR A DOLLAR.
At that time, placing edge devices on coins added a great deal of time to the coin production process.
Then, workers at the first Philadelphia Mint struck coins on manual-powered screw presses. Each of the presses housed a single pair of dies, one obverse and one reverse. The hammer (upper) die was attached to a movable vertical column much like that on the planchet-cutting press. The anvil (lower) die was fixed into place.
At first, a press operator placed a planchet onto the anvil die by hand. Shortly after the Mint opened,
Adam Eckfeldt invented a feed mechanism. Planchets were fed onto the anvil die by a tube loaded with the blanks. The mechanism was safer for the press operator, who could easily lose a finger in the press if the dies came down on his hand while placing a planchet or removing a coin.
The earliest U.S. coins were struck inside an open collar that surrounded the dies loosely and prevented the edges (including those with edge lettering and other decorative edge devices) from being crushed, until the 1830s, when the close collar was introduced gradually. The open collar, however, still restrained outward metal flow, though not as well as modern close collars do.
The machine used to impart edge lettering on those earliest coins was called a "Castaing machine," named after Frenchman Jean Castaing. In the 1680s, Castaing made improvements to a machine created earlier in the London Mint by Pierre (or Peter) Blondeau.
The milling machine was man-powered, with one operator needed for each machine, and imparted edge devices before the coins were struck.
Perhaps the best explanation of how a Castaing device works can be found in The U.S. Mint and Coinage by Don Taxay.
"This ingenious machine was built on a table and consisted primarily of two parallel bars, one fixed and one movable, each containing half the device," Taxay writes. "The movable bar was grooved at the top, and slid along a thin rail. The operator placed two planchets between the bars and gave the crank a partial turn. This rotated a cog which worked along the rack, thrusting the moveable bar forward sufficiently to entirely rotate the planchets. The distance between the two bars could be adjusted by means of two large screws which held the fixed bar."
Sometimes an error would occur when placing the lettering on the coins. Slippage of the edge-lettering equipment could produce a partial or complete overlapping of words on the coin. A half dollar, for example, with such a garbled edge inscription as FIFTY CENTS ORLF A DOLLAR is a product of slippage, and is definitely a Mint error. Such overlapped letters on the edge of the
capped bust half dollar are common.
The Castaing device was a very time-consuming way to add edge devices to coins. Taxay estimated no more than 10,000 coins per day could be milled. Moreover, since the edge devices were put on the planchets before they were struck, the words had to be incuse (lowered), to prevent their removal or damage during the strike.
Full story:
http://www.coinworld.com/news/050806/BW_0508.asp 
Posted 05/01/2006 01:15 am
