Commemorative coins derive their value from intricate artwork and outstanding quality. Creating these coins requires dedication to precision and attention to detail. But the process itself is relatively simple, involving only five steps:
- Designing the artwork: While creating coin designs was once done with a pencil and paper, the process is often now done by computer. Ideas for artwork must be created for both the obverse and reverse sides. If the coin is part of a series, the design must fit with the overall purpose and style. For instance, all the coins in the Classic Cars series feature sleek lines and a colored background, for a consistent appearance.
- Creating a model: Before a die can be made, a model of the coin must be created. Generally this model is much larger than the actual coin will be, so that all the fine details can be included in the sculpture. If the coin will be low relief, with a simpler design, an artisan sculpts out the details directly on a titanium plate. However, for high relief coins with intricate designs, an artisan first creates a negative sculpture of the coin using clay, and a plaster cast is made.
- Fabricating a custom die: Either the plate or the model is converted to a die, using a machine outfitted with an electronic stylus. The die is inspected, so that minor imperfections can be removed, and the die is heat treated to make it hard. Die hardness is measured on the Rockwell scale. Only dies that rate 58-60 are suitable for minting—dies that are too hard can become brittle ad break, while dies that are too soft will wear out too quickly.
- Obtaining coin blanks: Most commemorative coins are forged from precious metals, which come in bars. These bars are melted down, and the hot metal is poured into cylindrical containers called billets. An extruder pushes the metal out through a narrow rectangular opening in the billet, forming a long ribbon of metal. This metal is rolled to the desired coin thickness, and stamped out into blanks, or planchets, with a machine that resembles a cookie cutter. Each blank is cleaned and polished to the desired finish.
- Striking the coin: Each blank is fitted into a collar, which is etched with any details for the coin’s edge. Once in the collar, the coin is the pressed between two dies (one for each side). The pressure and duration of each strike depend on the coin’s composition, but usually the pressure is several hundred pounds psi. The number of strikes is determined by the material and the desired finish of the coin. This process often used to result in error coins, although these have become less common as coin minting has become more mechanized.
While many coins are complete after the striking process, others receive a final finish. Mirror, antiquated, and colorized finishes are all popular among collectors. These final treatments are carefully applied, to preserve each coin’s delicate, precise details.
This information is provided for general reference purposes and does not constitute professional advice. For detailed coin collecting or investing information, please consult with a professional expert.