Edge errors

There are various techniques used to emboss the design elements on the edge of a coin. One method involves using a machine called a straight edger during the hemming process, which both defines the effective diameter of the planchet and coins the edge. Another technique involves performing this operation simultaneously with the minting phase, where inscriptions and decorations are present in negative on the collar. The compression of the planchet against the walls of the collar transfers the design elements to the edge of the coin.

However, errors can occur during the coining of the edge due to various factors. These include incomplete integrity of the engraving caused by deformation, wear, or breakage of the characters. In addition, errors may result from mistakes made by the operator during the composition of the legend or due to slippage of the machinery.

In rare instances, an error in the assembly of the broken shell, a type of collar composed of three segments used during the typing operation for coins that require minting on the edge with the design elements in relief, can occur. This error may occur due to the negligence of the press operator or may be intentional. In such cases, the broken collar is assembled with inverted segments, resulting in an error on the coin’s edge.