Until It Breaks

Until It Breaks

Repeated stress of striking coins can wear down machinery, creating unique – and collectible – coins
By John Dale Beety of Heritage Auctions

Like factories, the U.S. Mints in Philadelphia, Denver, San Francisco and West Point use heavy machinery to make the billions of coins produced for the country each year. Also like factories, U.S. Mint machinery breaks down and has to be replaced, especially the metal cylinders called dies that are installed in coinage presses and come in direct contact with the coins themselves. Two dies are used to strike each coin; when a round metal blank is put between two dies and squeezed by a coinage press, a new coin is what pops out when the dies are pulled apart.

The repeated rapid stress of striking coins will wear down a die, and a worn die used too long will crack and then break up with chunks of the die falling away. When that happens, the coins struck by that die show the effects. When a crack opens up in a die, that creates a void for squeezed metal to fill, and a coin struck from a cracked die will show a raised line of metal as a result. A coin struck from a broken die will leave a void where the missing design should be, and the larger the break, the larger the void.
Early in the U.S. Mint’s history, when its future was uncertain and its budget small, there was immense pressure to save costs any way possible. By studying many specimens struck by the same die, advanced collectors of early U.S. coinage can see how a die cracked and broke up as it was used, tracing its status from perfect to “terminal.”
The 1811 half cent obverse known as Cohen-1 eventually lost a large chunk out of its left side that affected four of the stars surrounding Liberty’s portrait. The obverse die was taken out of service soon after the coin illustrated here was struck, as it became too damaged for even the early U.S. Mint to use.
Die breaks happen on modern coins as well.
The Roosevelt dime illustrated here has no date, for that part of the die was lost in a massive break. A negative partial impression, or clash, in front of Roosevelt’s profile indicates that the obverse die smashed into the reverse die when they were brought together without a coinage blank in between; the stress of steel striking steel with tons of pressure surely shortened the life of the obverse die.
While the U.S. Mint’s quality control is far more stringent now than in the 18th and early 19th centuries, this dime escaped detection and made it out to circulation, and now it is a dramatic reminder of what can happen when a piece of machinery in that money-making factory reaches its breaking point.
JOHN DALE BEETY is a numismatic cataloger for Heritage Auctions. This story originally appeared in The Intelligent Collector magazine (www.IntelligentCollector.com).
©2013 Heritage Auctioneers & Galleries Inc.