Our first example is a blank planchet, or coin blank. The clipped planchet error occurs during the stamping process, where thin sheets of metal are fed into a stamping machine that punches out rows of coin blanks. A straight clip, on the other hand, comes from an incomplete stamping along the edge. This is another relatively common error. Off Center Striking One of the more dramatic errors, the off center strike happens, as the animation illustrates, when a coin blank is mis-fed into the coin press and only part of the planchet is struck.
Some collectors make clocks with an appropriate off center coin at each hour on the dial face.
The double or multiple striking error can be the result from several situations. As the illustration shows, a double strike can occur from one die. However, the Mint utilizes two to four dies in close proximity to increase production. A multiple strike could also happen when a coin is struck, then bounces from table vibration into the path of another die. At press speed of two strikes per second, this is a possibility, as are other scenarios.