Prior to the establishment of the Soho Mint in 1789, most coins produced were struck
by hand presses. They were not necessarily regular in diameter and could be uneven
and misshaped. Matthew Boulton employed Jean-Pierre Droz, a Swiss engraver who had,
in addition to excellent engraving skills, designed a collar, or ‘plateau,’ which
acted as a third die that worked in addition to those stamping text and imagery
on the obverse and reverse sides of a coin or token. The collar was used to enclose
the blanks so that the two faces and the edge of the piece were all struck with the
same blow of the coining press. The edge could be plain, patterned or have an inscription
engraved on it.
However, the Droz collar proved unsuccessful, and was modified by James Lawson in
1790, resulting in a successful single piece collar that worked with an automatic
layer-in that delivered blanks, and removed the struck coins, medals or tokens from
With the use of collars, each coin became ‘perfectly round, and of equal diameter;
which is not the case with any other national money ever put in circulation.’
The Royal Mint was not able to introduce collars successfully. Boulton wrote in 1789:
I have also heard of an attempt to strike crown pieces at the Tower in
collers, but it was found so troublesome and the coller so hazardous that I believe
there never was half a dozen of them struck, and if such a thing had been proposed
to the moneyers they would have concluded that it would be worth a peny at least
to make a half peny.’
Eventually minting apparatus made at Soho Mint was introduced at the Royal Mint.
The Droz collar, having proved unsuitable for coining large quantities of pieces,
remained in use at Soho for proofs and medals.
Lawson’s modified collar introduced by Matthew Boulton and his team at Soho Mint
gave rise to our modern coinage.