Rotated Dies : Explanation and measurement.

It can be difficult to measure the degree of rotation on a coin that has rotated dies. I saw many posts asking about how to know the degree of rotation or which die is rotated. The gauge I developed below is based on an old device called a rota-flip. On a rotated dies error, there is no way to tell which die is the culprit, hence the term "rotated dies". Mint tolerance is 8 degrees, but these are usually not collected until they reach a 15 degree rotation or more. All US coins have a 180 degree rotated reverse, meaning if you are holding the coin with the obverse side up, facing you, the reverse side will be facing down. This is called coin orientation, as opposed to medallic orientation where both the obverse side and reverse side are upright at the same time. Dies can be rotated up to 180 degrees. Feel free to print this out and share it. Click on the visuals to enlarge.

Coin die rotation gauge.

Coin die rotation gauge explanation.