Tool and Diework
mint or medal plant: production work and one-of-a-kind tooling. Because of the quantity of dies needed much of the work includes shaping the dies to fit a particular press (turning dies on a lathe to a profile) and die polishing for proof coinage. This is all production work. The other tasks in the tool and die department require highly skilled tool and dieworkers to create the unique tooling, the collars, special blanking, trimming or piercing dies of a prescribed shape (or machine parts for equipment that infrequently break).Turning collar dies. Shaping the dies to fit a particular press, creating a profile to fit within a collar, is a production task. Dies come from the hubbing press as cylinders of steel. To create the neck and shoulder long enough to fit within the collar the die is centered in the chuck of a lathe and cut with a tool bit. Coining presses of different manufacturers require a different profile so the tool and dieworker must know which press he is preparing dies for.Prior to 1964 at the U.S. Mint a typical tool and diemaker could trim and shape 12 dies per day. When a need developed for a large number of dies very quickly (to strike new copper nickel clad coinage) a process utilizing a template was introduced which boosted production to 28 dies per man/day. Later a specialized lathe was imported from Europe which was able to turn and shape up to 250 dies per man/day. Proof die polishing. Dies intended for striking proof surface are first turned on the lathe to the correct profile, then polished on the areas of a die to have the highly reflective surface. Proof polishing is done with diamond dust as a polishing compound and a hand-held grinding wheel. See proof finish.Other tool and diework. The greatest talents of a tool and diemaker are required to make tooling for any new item in which the correct tooling is not already in existence.He must be able to examine the specifications then create a new collar, or the entire die set for blanking, trimming or piercing. The punch and plate must be made for each and fit precisely. These must be assembled into the die set to perform perfectly. Often a machine part that breaks is reproduced in the tool and die department.
excerpted with permission from
For Artists, Makers, Collectors and Curators
COMPILED AND WRITTEN BY D. WAYNE JOHNSON
Roger W. Burdette, Editor