Description:The pitiful state of the national coinage owing to counterfeiting and shortages irked Matthew Boulton for many years. Once the Boulton and Watt steam engine was capable of rotary motion, he was able to contemplate making coins using steam power. The rebuilding of the water mill in 1785, significantly increased his rolling capacity, so that potentially sufficient copper could be flattened into sheets. In 1786 he met a Frenchman in Paris, Jean Pierre Droz, who had devised a collar that would ensure that the coins would be struck consistently ‘round and all of one size.’
Most of all Boulton wished to obtain contracts for the national coinage and he spent much time in London lobbying officials and committees. Feeling encouraged by what he heard, or thought he had heard, in early 1788 he began building the first steam engine powered mint in the world. This was placed in Boulton’s garden about 100 yards from the ‘principal building’ of the Manufactory. The choice of location was unusual, but was determined by a need for secrecy – to keep prying eyes away from the ‘white-hot’ technology of the day. Boulton had already built himself a group of garden buildings including a menagerie, tea room, fossil room and laboratory. The new coining press room and engine house were concealed in the ‘farm yard’ behind these buildings.
Many ways of imparting motion to the fly of the coining presses were tried before a horizontal cam wheel turning above the coining presses arranged in a circle was conceived towards the end of 1788. In the same year a steam engine was installed at the one end of the water mill in the Manufactory to power laps (polishers), leaving the water wheel free to move only the rolls for flattening copper. The ‘Lap Engine’ was also connected to a new machine that cut out coining blanks. Boulton remained optimistic about the national coining contracts and proceeded to complete his mint.
In 1790 the patent for his mint machinery was obtained but no contracts from the government. Boulton and his team of engineers had solved the technical problems of making coins rapidly and of consistent size and shape, but it was not until 1797 that Boulton achieved his ambition of coining for the government.