Contrary to suspicions occasionally voiced by novice collectors, most minting errors are purely accidental. But there’s no denying that some errors have gotten a human assist somewhere along the way.

“Assisted errors” are those that had help in either their production or their release from the Mint (or both). Error coins created expressly for the hobby trade can be termed “intentional errors.”

It’s not always easy to distinguish assisted and intentional errors from those that arise by accident. The key to discriminating between these two populations lies in an informed assessment of pattern and process. Does the coin violate the constraints imposed by the minting process? Is the sequence of events so improbable as to beggar the imagination? Do relative abundance, raw abundance and the presence of unexplained spikes of highly unusual errors point to human intervention?

It is generally acknowledged than any oversized or misshapen Proof coin had help getting out of the Mint. Proof coins are only released in Proof sets sealed in plastic. Each coin occupies a tightly-fitting hole in a common mounting plate. A coin unable to fit into its respective hole could not have been released in a Proof set. While some of these Proof errors may have been made-to-order, others are probably accidental products of press malfunction. It’s the manner of their release which marks them as assisted errors.

Some errors impossible

Some errors are considered impossibilities from the standpoint of normal press function and design. A planchet or coin struck with a design intended for a smaller denomination has traditionally been considered a “forbidden” error. An oversized coin or planchet could not fit into the feeder tube or feeder finger and therefore could not be fed into the striking chamber.

Illustrating this “forbidden” error type is a 1977 Canadian 5-cent coin struck a second time by 1978 cent dies.

I’m not fully convinced that all such errors are impossible. After all, such an error can be produced accidentally if press operators fail to change the feeder assembly when switching dies from a larger to a smaller denomination. A coin left in a hopper or conveyor from the earlier press run could then make its way to the striking chamber unassisted.

Even so, I’m quite confident that the Canadian coin is an intentional error. Two different dates on an already improbable error are a bit hard to swallow. More importantly, the year 1978 produced a bumper crop of cent designs struck on larger planchets and coins, far too many to be accidental. I’ve heard from several independent sources that the Royal Canadian Mint actually set up a cent press that would strike visitors’ coins at the end of their tours of the RCM facility.

In 1981 the Philadelphia Mint produced its own rash of similar errors. They include a Lincoln cent struck on a 5-cent planchet, a cent design struck over an Anthony dollar and a dime design struck over a cent die cap. In each case, only the obverse is die-struck. All of these errors are uniface — struck against an underlying planchet.

Sometimes a coin is so bizarre that it is impossible to conceive of it as an accident. A prime example is the illustrated undated dime, which was struck slightly off-center on a burnished Proof planchet. A small circle of die-struck design occupies the center of the reverse face. It was delivered by a circulation-quality (“business strike”) die. The die-struck circle lies opposite a deep pit on the obverse face. Whatever object generated this pit provided the resistance necessary for the reverse die to leave an impression. Elsewhere on the dime there is no trace of die contact on either face. It therefore would seem to be a unique manifestation of an “invisible strike.”

An invisible strike occurs when the dies are too far apart at their closest approach to leave any design on the planchet. However, when another planchet, a previously struck coin or a foreign object intrudes into the striking chamber, it takes up the excess space between the dies and permits an area of die-struck design to form opposite the respective brockage, indent or struck-through error (see Collectors’ Clearinghouse May 3, 2010, and Sept. 20, 2010).

The pit is bowl-shaped in cross-section and carries a peculiar knurled texture. The right side of the pit appears to show a brockage (incuse mirror image) of the lower of the two acorns that adorn the reverse face.

This coin invites rampant speculation concerning its nature and origin, speculation that is given free reign in the November/December 2006 issue of Errorscope.

Coin World’s Collectors’ Clearinghouse department does not accept coins or other items for examination without prior permission from News Editor William T. Gibbs. Materials sent to Clearinghouse without prior permission will be returned unexamined. Please address all Clearinghouse inquiries to cweditor@coinworld.com or to 800-673-8311, Ext. 172.