Thinktank Birmingham - object 1960S01284(1) - Janvier reducing lathe

A Reducing Machine was a type of

pantograph A pantograph (, from their original use for copying writing) is a mechanical linkage connected in a manner based on parallelograms so that the movement of one pen, in tracing an image, produces identical movements in a second pen. If a line dr ...

lathe A lathe () is a machine tool that rotates a workpiece about an axis of rotation to perform various operations such as cutting, sanding, knurling, drilling, deformation, facing, and turning, with tools that are applied to the workpiece to c ...

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

US Mint The United States Mint is a bureau of the Department of the Treasury responsible for producing coinage for the United States to conduct its trade and commerce, as well as controlling the movement of bullion. It does not produce paper money; tha ...

who operated one as late as 2008 when it was replaced by CNC milling machines.

History

Contamin Pantograph

From 1836 to 1867 the

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 A treadle (from oe, tredan, "to tread") is a mechanism operated with a pedal for converting reciprocating motion into rotating motion. Along with cranks, treadmills, and treadwheels, treadles allow human and animal machine power in the absenc ...

. Hill sold his idea to

William Wyon William Wyon (Birmingham 1795 – 29 October 1851), was official chief engraver at the Royal Mint from 1828 until his death. Biography Wyon was born in Birmingham and, in 1809, was apprenticed to his father, Peter Wyon who was an engraver a ...

, the then chief engraver at the

Royal Mint The Royal Mint is the United Kingdom's oldest company and the official maker of British coins. Operating under the legal name The Royal Mint Limited, it is a limited company that is wholly owned by His Majesty's Treasury and is under an exclus ...

who sold a machine to the

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

in 1901 and by the

in 1907.

EXTERNAL LINK Royal Mint Reducing Engine webpage https://www.royalmintmuseum.org.uk/journal/curators-corner/janvier-reducing-machine/

References

{{reflist, 30em Lathes Metalworking tools French inventions