Definition: A hub is a positive, or relief (raised) image of the coin which has been impressed into a steel die during the process of creating coin dies. The original coin image is actually a plaster sculpture about 8 to 12 inches in diameter, from which a Master Hub is created using a special process that reduces the image to actual coin size. This Master Hub, which bears a relief image of the coin design, is then copied into a select number of Master Dies, (which bear the negative, or incuse image of the coin.)
The Master Dies are then copied, using a special extremely high-pressure "squeezing" process which employs tremendous hydraulic force, to create the numerous Working Hubs (commonly called simply hubs.) Then, from the tens of thousands of Working Hubs, the mint creates the Working Dies, (commonly just called dies.) It is from these working dies that our coins are actually struck.
The coin image on the hub is always a positive, or relief image, and the image on the die is always a negative, or incuse image. In this way, when our coins are struck, we get the raised detail we expect on our circulating coinage.
The coin hub itself looks just like a coin die, with the exception of the relief image. It is comprised of a steel shaft with the image of the coin impressed into one end of it.
The Master Dies are then copied, using a special extremely high-pressure "squeezing" process which employs tremendous hydraulic force, to create the numerous Working Hubs (commonly called simply hubs.) Then, from the tens of thousands of Working Hubs, the mint creates the Working Dies, (commonly just called dies.) It is from these working dies that our coins are actually struck.
The coin image on the hub is always a positive, or relief image, and the image on the die is always a negative, or incuse image. In this way, when our coins are struck, we get the raised detail we expect on our circulating coinage.
The coin hub itself looks just like a coin die, with the exception of the relief image. It is comprised of a steel shaft with the image of the coin impressed into one end of it.
Examples: It is during the process of making working dies from the working hubs that most of the doubled die errors occur.
