Coin Errors (Part 3) - Planchet Errors

The process of creating a coin begins with a blank metal disc being punched from a metal sheet. This seemingly simple step marks the start of the coin's journey, as it is transformed from a plain piece of metal into a valuable and recognizable form of currency.

Before a blank can be considered ready for coining, it must pass through an upset mill. There the blank is squeezed to a smaller diameter and is simultaneously provided with a low proto-rim at the outer margin of each face. In this way a blank becomes a planchet.

Now let us look at some coin errors which pertain to coin Planchet.

Clipped Planchet (Curved)
Planchet are punched from large thin metal sheets. After a section of the sheet is punched, if the sheet fails to be fed far enough ahead, the punch will overlap an already punched area causing that planchet to have a circular "clip" of missing metal.

Clipped planchet (Straight)
If the metal strip shifts during the punching process and the punches overlap the straight side edge of the strip, a straight area of metal will be missing from the planchet.

Cracked Surface
The phenomenon of a coin developing multiple cracks on its surface, resembling a piece of dry land, is known as the "DROUGHT error." Over time, the lamination of a coin can deteriorate, leading to this unique appearance.

Die Cap
When a coin is struck and sticks to the die for numerous strikes, the metal flows up around the die and the coin takes on the shape of a bottle cap. A very eye appealing and desirable error.

Indent
When a blank planchet partially overlaps another planchet in the striking chamber and gets struck, the overlapping area on the struck coin will exhibit a blank indented area from the other planchet being struck into it.

Lamination
Dirt and impurities in the metal of the planchet can manifest themselves as cracks and peels on the struck coin.

Split Planchet
If the impurity is severe enough, it can case the planchet to split into two halves. If the planchet splits before the strike, the resulting coin will be thin and have detail on both sides but often intermingled with rough striations from the impurities. If the planchet splits after the strike, one side will have full detail and the other side will be blank and striated. In either case the coin will be thin.

Uniface
This is a coin which was struck through another coin, so that no design is present. It is a “100% indent” effectively. This can occur when two planchet are fed into the press at the same time, and they are struck against each other. When struck, one side will be "uniface", which is to say, it will have no design, and the other side will have a very strong strike.

Wrong planchet/off metal
When a planchet is struck by a pair of dies that do not correspond to the denomination intended for the planchet, a wrong planchet error occurs. For example, a Rupee 2 coin struck on a Rupee 1 planchet will have the same weight and composition as a rupee 1.