Types A, B and BX fabricated hammer mills use a series of hammer or ring blows to crush, grind and pulverize materials. They are useful for size-reduction applications involving alum cake, gypsum, limestone, salt cake, wood, and bran. Type A up-running mills feature 2-stage dual mechanical reduction, whereby the revolving hammers shatter materials upon entry, then the reduced pieces are further disintegrated by contact against the breaker plates. Type B down-running, heavy-duty mills use heavy, reversible hammers with the manufacturer’s saw-tooth breaker plate to produce uniform product.