Presidential $1 Error Coins: 2007 Proofs
Posted on 11/13/2007
In this article we’ll take a look at one area of Presidential $1 error coins that has not gotten much publicity. We’ll examine the proof issues.
As a general rule, modern proof error coins are scarce. There are several reasons for this. The requirements of special production hinder the number and types of errors that can occur. For one, during production of proof coinage, dies are frequently replaced and, therefore, many of the errors associated with late-state die failure seldom occur. Also, proof coins are placed into special packaging which means that any aberrantly shaped error coin will likely be discovered at the packaging stage. And last, the Mint employs an exceptionally high level of quality control surrounding the production of proof coinage.
NGC did, however, receive a Proof Presidential $1 error coin almost as soon as we began receiving submissions. Surprisingly, this was a relatively dramatic and scare type of error, a coin struck from nonparallel dies also called horizontally misaligned dies. This type of error occurs when the dies are not level with each other during striking. The result is a “wedge-shaped” coin. The misalignment also creates a gap between the collar and the dies. During striking, metal will flow into that gap forming an enlarged and distorted, raised rim or flange. A handful of similar errors of this type have been seen by NGC.
|Left: Proof 2007-S John Adams $1 struck from horizontally misaligned dies, obverse view
Right: Proof 2007-S John Adams $1 struck from horizontally misaligned dies, reverse view. Click images to enlarge.
|Left: Detail of raised rim or flange of proof 2007-S John Adams $1 struck from horizontally misaligned dies.
Right: View of edge of proof 2007-S John Adams $1 struck from horizontally misaligned dies, showing wedge-like shape.
Click images to enlarge.
|Left: Proof 2007-S George Washington $1 struck from horizontally misaligned dies, obverse view.
Right: Proof 2007-S George Washington $1 struck from horizontally misaligned dies, reverse view.
Click images to enlarge.
Another interesting error found on proof issue Presidential $1 coins is a partial collar. Unlike circulation issue Presidential $1 coins, which received their lettered edges in a secondary process, the proof coins are struck with a segmented, lettered-edge collar. The partial collar error occurs when the collar is slightly out of place and therefore does not properly confine the coin’s edge during striking. When this type of error occurs with a segmented collar, a flange of extruded metal can form, like the raised rim seen on the misaligned die errors shown above. Further evidence of the improper positioning of the collar can be seen by the raised position of the edge lettering. This is illustrated in the proof 2007-S James Madison $1 partial collar error illustrated below.
The raised flange can also be seen at the right hand side of the image. Click to enlarge
A third type of error that has been encountered on proof Presidential $1 coins is a die crack, shown above on the reverse of a 2007-S Thomas Jefferson $1 coin. A die crack occurs when a small crack in the die allows metal to flow into the damaged area during striking. On the surface of the coin, this appears as a thin, irregular, raised line. If the cracked die remains in production, more extreme errors can result, including a cud, an raised portion of a coin’s surface corresponding to an area on the die where a piece has broken away. Die cracks are relatively common on circulation issue coinage (mint state coins) and small cracks can fall within the Mint’s accepted tolerances. Dies are replaced when a large crack appears. On proof coinage, however, coins with die cracks are deemed outside of acceptable tolerances and, when detected, are culled during quality control. For this reason, even small die cracks on proof coinage are deemed to be mint errors by NGC.
Stay tuned for updates and NGC articles on other coins in this series as more errors are discovered and reported.