The Evolution of Minting Technology–Part 4
In Part 4 of this series, explore how steam power, toggle presses, and industrial innovation transformed coin production during the late 18th and 19th centuries.
One of the most transformative periods in the history of minting technology was between the late 18th through 19th centuries. The mechanical innovation of this time is largely attributed to Matthew Boulton.
Before the 1700s, most coins were produced using hammered methods or screw presses. It was labor-intensive, and the coins were prone to irregularities in weight, thickness, and strike quality. Because of this, counterfeiting and clipping were persistent problems. With the invention of the Castaing machine in the late 1600s, these issues were beginning to be addressed.
In 1762, Matthew Boulton built the Soho manufactory near Birmingham, which later became known as the Soho Mint. His factory produced small metal articles such as buttons and buckles. In 1768, Boulton met James Watt, a fellow engineer. Watt had invented a steam engine, and when his business partner went bankrupt, Boulton stepped in. The new machines helped power Boulton’s factory, and in turn, Boulton saw the potential. He urged Watt to design the double-acting rotative and the Watt engines.
Photograph courtesy of Wikimedia Commons.
In 1786, Boulton applied steam power to minting machinery. At the time, counterfeit coins had flooded the market, and Boulton realized they were just another small metal product. He had easy access to a supply of copper, so it only made sense to get into the business. In 1788, he established the Soho Mint as part of his industrial plant. He was able to acquire the patent in 1790 for the steam-powered coin presses and subsequently began to provide coins for the East India Company. It wasn’t as easy to get a license to strike British coins. Boulton had even begun sending planchets to the newly founded Philadelphia Mint in the United States before he was given a contract to strike coins for the Bank of England in 1797.
Boulton, with the help of German medalist and coin designer Heinrich Küchler, designed new coins with better security features, making it difficult for counterfeiters to copy. His efforts amounted to the “Cartwheel” coins, which were perfectly round and had exact measurements.
While Boulton revolutionized powered minting, Diedrich Uhlhorn, a German engineer, refined the mechanics of the coin press itself. In 1817, Ulhorn invented the toggle press, a breakthrough that dramatically improved efficiency and strike quality. Uhlhorn developed the toggle-joint coin press, which allowed for coins to be struck at a much greater speed compared to the manual screw presses.
Photograph courtesy of Wikimedia Commons.
Across the ocean, the U.S. Mint was struggling to keep up with demand. Franklin Peale was hired in 1833 to travel to Europe and observe their processes. The original mission was to study a new process of refining gold and silver in Paris, as well as learn about the coining technology powered by steam. It was important that Peale be able to return to the U.S. and provide direction for new machinery to be built. He studied the “humid” method for assaying and took detailed notes on the process and the tools involved. He also purchased a set of these tools.
Peale continued and learned the methods for parting at a refinery in London, and would eventually travel to mints in Germany as well. He was able to bring back many ideas to advance the Mint and its equipment. Peale brought steam-powered machinery, inspired by Boulton’s in Soho, and helped facilitate the transition from screw presses to Uhlhorn’s toggle presses.
By the end of the 19th century, coin production had been fully industrialized. Coins were no longer artisanal objects, but precision-engineered products.
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