The E-Sylum:  Volume 7, Number 46, November 14, 2004, Article 22


  Dick Johnson writes: "I accept Chris Faulkner's request
  for information on the upsetting machine. We cannot say
  it was invented, it was more like "developed." But we
  do know who should receive credit - Matthew Boulton!
  If there is one person who was responsible for modern
  coins and coining technology it was Matthew Boulton.

  Every numismatist should build a shrine to this one man
  -- we would not have modern coins, or perhaps, modern
  numismatics -- without this manufacturing genius. (I will
  put his picture on my wall next to Leonard Forrer who is
  my hero for compiling a directory of world coin and medal
  artists, what I am trying to do for American artists).
  [And a thank you also, to Dick Doty for his fantastic 1998
  book on Matthew Boulton "The Soho Mint" - Dick, send me
  your picture, I'll put it next to the others!]

  Before Matthew Boulton, coins were essentially struck on
  the manual screw presses. Blanks were fed by hand one at
  a time. I won't say it was a slow process, I was amazed
  to learn they could strike as many as 20 to 30 a minute!,
  as several men swung the arms of the screw press around
  and back while the "coin setter" retrieved the struck coin
  and inserted the next blank. They had great rhythm!

  Boulton took his partner James Watt's invention, the
  steam engine, eliminated the men swinging the arms and
  applied steam power to the screw press. Boulton learned
  of Jean Pierre Droz's (and Gengembre's) invention at the
  Paris Mint of an automatic feed and delivery system which
  could be attached to the screw press. Boulton hired Droz
  in 1790 for his Soho Mint in Birmingham (Droz makes
  improvements, engraved some dies, but returns to France
  nine years later).

  Existing blanks at first jammed the press (imagine those,
  mint error collectors!) They needed blanks in quantity
  that were uniform and perfectly round for automatic feed.
  Cause of the trouble were the burrs around the trailing
  edge of the blank from the blanking die shearing through
  the metal strip.

  At first they hired young Birmingham boys, even 8 to 10
  years old, to put a handful of blanks in a leather bag
  and shake the hell out of the bag. The blanks knocked
  against each other and "deburred" the edges. Remember
  this is the beginning of the Industrial Revolution, so
  they had to find a better IR way. They did this by
  putting more blanks in a barrel and rotated the barrel
  a process similar today called "barrel tumbling"
  which is speeded up by adding steel balls smaller than
  the blanks so they can be sieved out later]. This action
  also deburrs the blanks.

  By 1797 Boulton's team had developed a machine he called
  a "rimmer" " still called that in England today " here in
  the colonies we call it an "upsetting machine." [I like the
   British term better, but rimmer sounds too much like an
  erotic toy for Americans to widely accept the term.]
  Boulton's rimmer did five things: removed the burrs,
  smoothes the edge, rounds the edge, made the blanks
  perfectly round, and thicken the edge.

  Modern upsetting machines still do these five things. Mint
  error collectors call blanks before upsetting "type 1" after
  upsetting "type 2." Type 1 blanks are fed into an upsetting
  machine and they travel in a channel on a spiral track
  through ever smaller and smaller walls which forces the
  blank's diameter to become less and less. The metal at the
  edge builds up on both surfaces, thus making the blank
  thicker around the circumference (ideal for raised rim

  To answer your second question, Chris, who else uses
  upsetting machines? I live near the Naugutuck Valley of
  Connecticut where machine shops and metalworking plants are
  on every block in every industrial area. I should ask some
  of these. But the obvious answers are anything that is
  "coined," that is stuck between dies at room temperature:
  Buttons, small parts, washers, rings, the list is lengthy.
  Some odd shaped parts are coined from round blanks because
  of the ease and speed of striking these, then trimmed to
  shape afterwards.

  I learned of the upsetting machine close up when Medallic
  Art Company bought its first coining press in 1967. We
  bought the press in Germany, but upsetting machines are made
  in England (okay, rimmers!) and we couldn't get one right
  away. My boss, Bill Louth, happened to mention this to Eva
  Adams, then Director of the U.S. Mint. "We got some we're
  not using," she said, "I'll lend you one." Sure enough,
  until a new one came from England, we used a U.S. Mint
  upsetting machine for upsetting blanks to strike medals!
  The first of these were the Illinois Sesquicentennial
  Medal of 1968 in silver dollar size."

  Wayne Homren, Editor

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