Fin
Fin. A sharp protruding ridge at the rim/edge juncture where excess metal squeezes out between the dies and collar on a piece struck in a coining press; flash on a coined piece.
A pressman would call it a burr and attempt to remove or remedy it; a collector would call it a wire edge in America, or a knife edge in England. It is caused by a worn collar, excessive pressure, an oversize or overweight blank or simply, sloppy presswork. The pressman needs to make some immediate adjustments because such fins create problems in ejecting coined pieces. It is more apt to happen on proof coinage, but is not diagnostic of proof coinage as it can occur in any coining operation. Such fins can be removed by chasing if the pieces cannot be struck anew. The goal of every pressman should be to coin pieces with sharp edges, this is, with 90° angles at the rim/edge juncture without any flash at all.excerpted with permission from
An Encyclopedia of Coin and Medal Technology
For Artists, Makers, Collectors and Curators
COMPILED AND WRITTEN BY D. WAYNE JOHNSON
Roger W. Burdette, Editor
excerpted with permission from
An Encyclopedia of Coin and Medal Technology
For Artists, Makers, Collectors and Curators
COMPILED AND WRITTEN BY D. WAYNE JOHNSON
Roger W. Burdette, Editor