Master block (or master holder)
A The process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. The machined recess in a die that gives the forging its shape. The forging operation in which metal is progressively formed to general desired shape and contour by means of an impression die (used when only one block operation is scheduled). primarily used to hold A piece of steel that is tightly fixed in a die. The insert may be used to fill a cavity, to replace a portion of the die with a grade of steel that is better suited for service at that point, or to function as a small die with the impression fastened to a master die.... More The metal blocks into which forging impressions are machined and from which forgings are produced..