Errors

Just a few examples ...

> Brockage
> Mistrike
> Cud
> Clashed dies
> Clipped planchet
> Double strike
> Mule
> Wrong planchet

| A brockage is formed when a coin is not ejected from the press and remains in place while another planchet is struck. The result is that the first coin acts as a die for the second coin and makes an incuse impression of the exposed face. It is not obvious from the picture but the image on the right is of a hollow face.
| A typical mistrike. The planchet has not engaged properly in the collar and so is struck off-centre. A fairly common error.
| A cud is formed when a die crack becomes so severe that a piece of the die breaks away.
| If a blank fails to feed into the press, the hammer and anvil dies may come into direct contact with each other. In such a case the harder die will leave an impression on the softer one. In this example from India, a mirror image of Victoria can be seen on the reverse side of the coin.
| A so-called "clipped planchet" error caused by a feed slippage in the blanking press. There are several features which distinguish the genuine error from a post-strike fabrication. Click here or on the picture for more information.
| A variation of the so-called "clipped planchet" error. This one was caused by a misalignment of the metal strip in the the blanking press such that the blank was punched from the edge of the strip. Click here or on the picture for more information.
| This coin was not fully ejected after it was struck and remained partly within the reach of the dies whereupon it subsequently received a second blow. This error is quite rare in Australian Commonwealth coinage.
| Occasionally, dies get mixed up. Here we have an example of a Fijian 20c coin struck with an Australian obverse. This sort of mismatch is called a "mule". The most famous example in Australian coinage is the 1916 halfpenny.
| Sometimes a coin is struck on a planchet intended for a different coin. In this example, a New Zealand 5c coin was struck on a 1c planchet. The coin weighs 2.50 g which is consistent with the 1c. A normal NZ 5c coin weighs 2.83 g.

Just to make things a bit clearer, here is a picture of the 1946 halfpenny brockage taken at a bit of an angle. That the brockage face is incuse can be seen clearly in this picture.

The brockage again

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Most recent revision: 1st December 2004 - added "wrong planchet" error.
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