Coin Collecting - Creation of Minting Tools

Minting tools include the dies from which coins will be stamped. At the completion of the coin design process an epoxy resin model of the coin face (known as a galvano) had been created, but it was many times larger than the coins that will ultimately be produced. The design must be greatly reduced in size, therefore, and transcribed onto hardened steel minting tools, which will be necessary in order to strike the coins.

Galvano_on_Pantograph

The galvano is mounted onto a pantograph, a machine that reproduces the design but at a greatly reduced scale. As a tracing stylus rides up and down over the features of the galvano, it will move a cutting tool that will carve the design onto the end of a steel rod. The design cut into the steel will be an exact duplicate of the galvano, but at the diameter of the final coin. The resulting steel rod with its image is known as a Master Hub or Master Hob. It is from this Master Hub that the dies will be created.

The Master Hub is heated to harden it. After hardening the hub is placed in a hydraulic press (known as a hubbing press) where it is pressed against another steel rod, squeezing the design onto it (this time, however, creating a negative impression). The process is known as "hubbing" or "hobbing" and the result is a Master Die.

From the Master Die, a Working Hub is created, and from that, several Working Dies are produced (all through the hubbing process). Approximately two Working Hubs will be made from the Master Die and from these hundreds of Working Dies. The Working Dies are used to strike coins.

Flying_Eagle_Hub_Die_and_Coin

Note: Cross-Sectional Relief is Highly Exaggerated