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Basin.  The concaveness or sloping surface of a model or numismatic item. A die in this shape is said to have a camber. The basin is formed by the rim and the dished area of relief. Coin models particularly are so shaped because of the requirement of a rim higher than any point on the relief and the fact coins are struck from a single blow. A background plate in this dished shape is also called a basin. The St-Gaudens 1907 $20 Gold ultrahigh relief is the most dramatic U.S. coin with a basin. 

Also the term basin is used by mints for somewhat smaller models while “background plates” is used for medallic art, often in a larger size. Should the design be flat without any concaveness certain modern diecutting pantographs can create a basin shape and cut a die with a camber. See BACKGROUND PLATE, die camber.

excerpted with permission from

An Encyclopedia of Coin and Medal Technology

For Artists, Makers, Collectors and Curators


Roger W. Burdette, Editor

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