ON THE PHILADELPHIA MINT'S JANVIER LATHES

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V15 2012 INDEX E-SYLUM ARCHIVE

The E-Sylum: Volume 15, Number 39, September 16, 2012, Article 13

I saw the 1907 Janvier lathe at the Mint and was astounded that it was that new. I had thought that the technology was decades older than that. Was the mint just slow to get on board?

Well, no - the technology had been around at the Mint and elsewhere. Knowing Roger Burdette had done a lot of research around St. Gaudens and the manufacture of his double eagle in 1907, I asked him to confirm that this particular Janvier machine was not the first one at the mint. Drawing on his research and that of Dick Johnson and others, he submitted the following discussion taken from the draft of his planned book, From Mine to Mint . Thanks! -Editor

Technology for copying and reducing machines dates to the late 17th century, with considerable progress being made in the latter 18th century by several machinists and inventors in France, Russia and England. Their original goal was to make reduced-side copies (or molds) of sculpture so that the copies could be sold to well-to-do families.

Russian machinist Andrei Konstantinovich Nartov seems to have invented a foot powered “medallic copier lathe” sometime before 1747 and described it in his 1755 manuscript, Teatrum Machinrum. The innovation was using a foot treadle to turn a cutting graver which, in turn, cut metal, or more likely cameo ivory and stone. But Nartov’s device did not enlarge or reduce the original design, it only copied it.

Belgian Henri Hulot, père added a pantograph feature and foot power to his reducing machine in 1766. “In 1788 Frenchman, Jean Baptiste BarthélemyDupeyrat built a slightly more advanced mechanism which was widely adopted among French artisans and sold to mints in England (Soho and the Royal Mint) plus the Karlsruhe Mint in Germany.” This gradually evolved through the hands of multiple machinists into steam powered versions used by Matthew Boulton.

James Watt saw a simple reducing lathe at the Paris Mint in 1802 and this inspired him to build a similar reducing device for portrait busts and other three dimensional objects. By 1809 the term tour à médailles or “likeness-lathe” was in use and the French version was capable of duplicating the comparatively shallow relief of a medal or coin into a reduced size steel copy. The work was much faster than hand cutting, but the product required considerable retouching before it was usable.

The US Mint had two earlier versions of model reducing machines: one made by Contamin in Paris, and on May 2, 1867 they bought a Hill lathe from H. W. Field in London. Janvier's machine was more sophisticated than its predecessors, and the addition of the two speed cones (called reduction gears at the time) further improved production quality.

The US Mint bought their lathe in November 1906 from Dietsch Brothers in New York and it was first used on the Barber/Morgan 1906 double eagle pattern used as a test prior to the Saint-Gaudens designs. Henri Weil worked for Dietsch Bros. at the time and was the one who trained Barber and Morgan on use of the new machine. He also was hired by the mint in January 1907 to help make the Saint-Gaudens reductions and hubs at the mint.

Several US companies made reduction machines, too. The largest was Keller Mechanical Co. Their equipment was not precise enough for the mint's need to cut complete hubs from models, but they later were a major supplier of large-format reducing machines to the auto industry.