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Hammer Mills


  • Motor drive directly coupled to rotor assembly. V-belt drive optional.
  • Large, obstruction-free product feed opening.
  • Convenient access door for rapid inspection and changing of screen assemblies.
  • Available with directly coupled or independently powered fan assembly.
  • 4-Way reversible hammer design.
  • Perforated and bar screen designs available.
  • 270° Cylindrical screen area minimizes residence time.
  • Peripheral hammer velocity of up to 24,000 feet per minute ensures efficient, rapid particle size reduction.
  • Extensive hammer designs and construction materials for varying requirements.
  • Easy maintenance

  • Heavy plate steel, welded and bolted fabrication (stainless steel optional)
  • Replaceable, abrasion-resistant steel liner plates available in maximum wear areas.
  • Dynamically balanced rotor assembly.
  • Easily serviced, hard-faced product breaker plates.
  • Dust-tight or water-tight construction
  • Special configurations

    Mill Case

    The mill case is welded steel construction and built in three sections. The lower half of case is one piece and upper half is in two sections. The feed intake section of the upper half is bolted to the lower half of case, resulting in a permanent, dust-tight connection between the feeding or loading hopper and the mill intake.

    The remaining top section is hinged for access to interior of the mill for changing hammers, hammer pins and screens. All mating surfaces are machined for an accurate, dust-tight fit. Single latch door for easy maintenance and cleaning. Gasketed door for dust-tight operation.

    Breaker Plates

    The initial reduction of material is aided by hard breaker plates located in feed intake section. Material, traveling at a high velocity hits the many fine hardened ridges of plates with a smashing impact to cause initial disintegration.


    The degree of fineness of the ground product depends upon the size of screen perforations. Screens are in two sections. In addition to the lower half-circle screen, Munson Hammer Mills have an extra quarter screen located in the hinged section of the top case. This increases the screen area by approximately 50% more than conventional designs, to 270°. Both perforated and bar-type screens are available.

    Note that with the extra top screen and breaker plates, every square inch of space in the mill case has been utilized for the efficient and rapid grinding of material, contributing to the superior performance of Munson Hammer Mills.

    Quick Screen Release

    The lower screen is held securely in place by a quick screen release mechanism, ensuring a tight screen fit to guard against leakage of fine dust, while it allows quick and easy changing of screens.


    The rotor shaft, on which the rotor is assembled, is accurately turned from alloy steel stock. Hammer discs, which hold the hammer pins, are separated by machined spacer discs. Hardened steel hammer pins have a removable ring at one end for easy replacement or changing of hammers. The ring is protected from wear by a hardened steel guard, exemplifying the lengths to which Munson has gone to achieve extreme ruggedness.


    For general grinding, standard equipment consists of both heavy and light hammers, although the number and arrangement of hammers may be varied where conditions warrant. Both weights of hammers have "step ends" and may be reversed so that all four edges can be utilized.