Doubled die

The coin error known as Doubled die is a result of a misalignment in the production phase of the die, specifically during the transfer of the image from the hub to the die that will be used in the money press. Dies are created using a hydraulic press that compresses the hub against a virgin die with a pressure of hundreds of tons. Due to the hardness of the steel used in the die, subsequent compressions cannot completely erase the previous compression. Therefore, if the hub and the die are not aligned in subsequent compressions, the image on the die will display signs of the previous compression, resulting in the so-called “doubling effect”.
This doubling effect can occur in two ways, affecting the entire face of the die or only one area, typically found in the center of the die. Depending on the type of misalignment, there are eight identifiable classes of doubled die errors.
Class I is Rotated doubling, which occurs when the hub is rotated on its axis in subsequent compressions, creating two split images on the die and the coins minted from that die. The strongest impression is made during the second compression, and the point of rotation is usually the center.
Class II is Distorted doubling, which occurs when a distorted punch is used in one of the compressions. This distortion may occur due to long-term use of the punch, resulting in a slightly distorted and stretched image towards the center or edges of the die.
Class III is Doubling with different imprint, which occurs when a hub is used in one of the compressions that has one or more elements slightly different or positioned differently.
Class IV is Displaced doubling, which occurs when the hub is displaced on its axis in any direction during subsequent compressions.
Class V is Doubling with pin, which occurs when the hub is rotated or moved by pivoting on a point on the face of the die. The doubling effect opens “like a fan” from the point that acts as a pivot, resulting in a maximum width at the point opposite the pin.
In addition to the five major classes of doubled die errors, there are also three minor classes. These minor classes are characterized by variations in the doubling effect that are less pronounced or less common.
Class VI – Distended doubling: This class occurs when the hub is compressed too strongly against the die, causing the metal to be pushed outward and creating a slightly distended image. This type of doubling is usually less pronounced and less common than the other classes.
Class VII – Pivoted doubling: This class occurs when the hub is rotated or moved on a point that is not located on the face of the die. In this case, the doubling effect will be more pronounced in the area opposite the pivot point.
Class VIII – Design rim doubling: This class occurs when the doubling effect is limited to the rim of the coin and does not affect the design elements. This type of doubling is generally less noticeable and less valuable than the other classes of doubled die errors.