Reducing machine
Type of pantograph lathe
A reducing machine was a type of pantograph lathe used until the 21st century to manufacture coin dies. Prior to the machine's introduction, designs were cut by hand into metal dies by a specialist engraver. The reducing machine changed this by allowing artists to create designs on a larger surface area and then have them scaled down and cut into a die automatically. The most successful version of the machine, created by Victor Janvier, was used by mints all around the world, including the United States Mint, which operated one as late as 2008, when it was replaced by CNC milling machines.
01History
Contamin pantograph
From 1836 to 1867, the US Mint operated the first die-engraving pantograph invented by a now-forgotten French inventor whom the machine is named after. It used a rotating cutter to copy a design.
Hill pantograph
During the mid 1800s Englishman C. J. Hill developed a variation of the Contamin whereby the electrotype was traced horizontally using a treadle. Hill sold his idea to William Wyon, the chief engraver at the Royal Mint, who sold a machine to the US Mint in September 1867.
Janvier reducing machine
In 1899, French engraver Victor Janvier patented a design which solved the inefficiency problem. By using twin cone belt drives that pointed in opposite directions dies could be cut much faster by increasing the speed as the cutting point moved outwards. After several days a reduction punch is produced, which is then used to produce working dies. Machines using Janvier's improved design were bought by the British Royal Mint in 1901 and by the US Mint in 1907.
Sources and credits
This article is adapted from the Wikipedia article “Reducing machine”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
Images, from Wikimedia Commons:
- Thinktank Birmingham - object 1960S01284(1) - Janvier reducing lathe.jpg by Birmingham Museums Trust, CC BY-SA 4.0
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