Expert: PAPAJACK - 6/20/2009

Question
I have an 1818 penny that when holding the face upright and flipping the coin over, bottom over top, the backside i not square to the face. Instead it is rotated a full 1/4 turn so that the top of its center of alignment points to 10:00. Is this common? U.S. coins currently flip over square front to back.

Answer
Hello Dennis,                      

The U.S. coinage uses what is called a COIN turn. As you stated modern coins are. There is a defect in manufacturing called a “Rotated Die Error”. I describe it below but you can find more on the web if you search for this error.

Most other country’s coins are produced using the MEDALIAC turn. This simply means that when the coin is turned over from left to right looking at the heads side that the reverse side is viewed right-side up as well.
As a medal you wear on a chain would be viewed right side up as it flips on your neck. Thus the term MEDALIC TURN just as a medal worn around your neck would need to be upright when it flips.

For the COIN turn the medal is always 180 degree offset. You have to flip it top to bottom looking at the heads side that the reverse side is viewed right-side up as well.

As for reason it was to be unique and basically different from the Spanish and mostly English coins that were the only form of coins in America prior to 1793, when the US opened its own minting facility in Philadelphia.

In the minting process a rotated Dies happens when the die or Punch Press machine wears, and the die begins to turn with each piece it hits.  This was more common in the older machines that US Mint used parts would often wear and dies would often break.

Thank You and Good Luck

PapaJack