Rimmer, Rimming. The British term for an upsetting machine and the process of treating blanks by edge thickening and marking perfectly round. This is the term originally used when the machine was developed by Matthew Boulton in 1790. Although these machines were built in England and exported to mints in America (and elsewhere, of course) the term did not cross the ocean with the machines and were known as upsetting machines as early as 1816 when first imported in America.

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C66 {1988} Cooper pp [early] 101-106, [modern] 193-199, 241.