E-SYLUM'S BEST: THE JANVIER DIE-ENGRAVING PANTOGRAPH

Dick Johnson also nominates:

Dick Johnson writes: "First, Darryl Atchison should be thanked publicly for asking the questions he did about the Hill and Janvier reducing machines in last week's E-Sylum. This is so important to the technology of die making for all types of struck numismatic items. Numismatists should have a basic understanding of engraving, dies, die making and die striking. Most don't. Darryl, thank you for asking about something so important!

I have been studying die-making equipment for 35 years, since I was hired by Medallic Art Company in 1966. I stood in front of the three Janvier die-engraving pantographs in MAco's New York City plant for hours marveling at this ingenious mechanism. And when the plant moved to Danbury in 1972 and we had more room, the firm acquired four more reducing machines as these came on the market.

I have tracked the history of this vital mint equipment to discover the ingenuity of one man - Victor Janvier (1851- 1911). Imagine inventing a piece of equipment that every mint in the world HAD to have. He developed, literally, a money-making machine. And the mints of the world beat a path to his Paris workshop after he patented it in 1899 to acquire his machines. He, of course, was not the first, but he developed the most advanced and successful die-engraving pantograph.

In all, there have been 22 people, firms and mints who had a part in developing this equipment throughout history. It has gone through five stages. The first stage was little more than a rotating drill (with a string bow like a Boy Scout starting a fire). It was used for cameo cutting.

The second stage applied peddle power to the fixed drill or cutter (peddled like an old sewing machine) for early die cutting. In the third stage water or steam was added as the power source and devices were cut in dies and lettering would, of course, have to be added later with punches.

Here you have Matthew Boulton using these machines at his Soho Mint and when his partner, James Watt, retired, he made refinements to Boulton's machines. The nationalities of the machinists who made improvements were French, British, Belgian and later, German. The U.S.Mint first had a French Contamin pantograph in 1836, which was replaced by a British Hill machine in 1867, and the French Janvier in 1906.

By the third stage it was a 'controlled milling machine' to cut dies. The pattern had to rotate in sync (synchronization) with the diestock being cut, both revolving on separate axis. Both the tracing point and the cutting point start at the center. A problem existed, however, that as the tracing point widened its circular path, the cutting point revolved at the same speed. Janvier recognized that the tracing point should slow down and the cutting point should speed up because it also was cutting a greater path, it was doing more work.

Janvier solved this problem mechanically with twin cone belt drives with the cones pointing in opposite directions. One belt controlled the rotating axes, the other belt carried the variable speed to the spindle controlling the cutting point -- as the tracing point tracked a wider circle Janvier's mechanism increased the speed of the cutting point. It worked!

That mechanism in pantographs he manufactured made Janvier wealthy but not famous. Today national and private mints know the name Janvier for their die-engraving machines, but few others outside mint historians even know his first name (Victor) and what he actually accomplished.

Today we are in the fifth stage of this machine. Modern die-engraving pantographs are so sophisticated, they can raise or lower relief, they can flip a design in contraposition (a left facing portrait can be changed to face right), they can also alter the slope of the background - metalworkers call this 'camber' - a basin background can be flattened, or a flat background can be given a slight basin shape. But most important - all the detail in the pattern can still be reduced and cut into the die in direct proportion to each other.

There is a saying among medalmakers - "if it's in the model, it's in the medal!" Thanks to the die-engraving pantograph, but thanks mostly to Victor Janvier.

Will there be a sixth stage of this miraculous machine? If so, the United States Mint will certainly put it to use. U.S. Mint information officer Michael White told me this week the Mint has several milling machines in house they are studying. A feasibility study is also under way, he says, for the possibility of laser cutting of dies.

Stay tuned. Die cutting science is not over yet!"

[The March 16, 2004 issue of Numismatic News contains a Viewpoint article by Michael P. Lantz about a group of Janvier reduction machines built at the Denver Mint in 1969. -Editor]

To read the complete original E-Sylum article, see: THE JANVIER DIE-ENGRAVING PANTOGRAPH (coinbooks.org/esylum_v07n11a10.html)

Wayne Homren, Editor

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