Collector Basics: A mishap during the blanking process causes incomplete planchet errors

Coin World introduces new collectors to a number of planchet errors
By , Coin World
Published : 12/04/14
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Editor's note: This is one in a series of Coin World Collector Basics posts on numerous types of planchet errors.

Incomplete planchets

Often, though erroneously, called a "clip," an incomplete planchet results from a mishap in the blanking process. If the planchet strip does not advance far enough after a bank of punches rams through the metal when producing planchets, the punches again come down and overlap the holes where planchets were already punched out.

Where the overlapping takes place, there is a curved area that appears to be "missing" from the planchet. If the strip slides to the side too far and the punches overlap the side of the strip, the missing area is straight. If the punches overlap the end of the strip, the missing area is either ragged or straight, depending on whether the end of the strip was trimmed.

The word "clip," commonly used, suggests a piece of a complete planchet was cut off, which is not the case — these error pieces are incomplete to begin with. "Clip," when accurately used, refers to the ancient process of cutting small pieces of metal from the edges of precious metal coins for the bullion; that is why U.S. gold and silver coins have lettered or reeded edges, to make it more difficult to clip a coin.

Many incomplete planchet errors have a "signature" known as the Blakesley effect. The area of the rim 180 degrees opposite the missing metal of the so-called "clip" is weak or nonexistent. During the rim-making process, the lack of pressure in the upset mill at the "clip" results in improper formation of the rim on the opposite side.

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