DIESINKING

process of machining a cavity in a steel block to be used for molding plastics, or for hot and cold forging, die-casting, and coining. The die block is mounted on a table while a vertical-spindle milling machine with end cutters is used to shape the die. In most simple machines the movement of the cutter may be controlled by the manual operation of transverse, horizontal, and vertical feeds. Patterns of sheet metal or plastic may be used as guides. A pantograph (q.v.), four light rigid bars in a parallelogram, may be used to cause the cutter to follow a certain layout. Diesinking is done chiefly by automatic machines. The movement of the cutter against the die block is controlled by tracing a finger gauge the size and shape of the cutter in contact with a previously made model of soft metal, plaster of paris, or wood. The model, or template, is attached to the bed beside the die block. The movement of the finger over the template is transmitted to the cutter by hydraulic or electrical controls. The surface of the sunken die is finished to the desired size and surface quality by hand scrapers, files, small grinding wheels, and polishing cloth.