NNP

Rocker Dies.  A pair of dies engraved on the curved interface surfaces, one convex and one concave. Unlike roller dies where the designs were engraved on cylinders and continuously rolled on a strip of metal (then blanked or cut out afterwards), an individual blank was impressed between a mated pair of rocker dies which were rocked back and forth under pressure until the design was struck up. This method required a special rocker press. It was intended to replace the screw press but did not.

Both of these coinage methods proved impractical: the rocker dies because of imperfect impressions and misshapen coins they created, and the roller die for the manual trimming necessary for individual coins after cutting out.

Reference:                                                                                                                                        

NE42 {1982} Doty, p 282.

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