This is also a process related to the manufacture of coins. A hub can be described as a positive, or raised image of the coin that has been impressed into a steel die during the process of creating coin dies. The original coin image is an enlarged plaster sculpture which is about 8 to 12 inches in diameter. A Master Hub is created from there using a special process that diminishes the image to actual size of the coin. This master hub, having the relief image of the coin is again copied into select number of master dies. This selected master dies bears the negative, image of the coin.
In a process called Squeezing, the master dies are copied under a very high-pressure that uses hydraulic force, to create many Working Hubs (or simply hubs). Then, the mint creates the working dies, (or just dies.) from the numerous working hubs. Our coins are actually struck from these working dies. The hub has always a positive or relief image, while the image on the die is always a negative, or incude image.