Replacing Hammer Mill Wear Parts
Any machine that has moving or rotating parts requires routine maintenance to ensure that it performs at optimal capacity. This is especially true of size reduction equipment which has grinding elements that will wear over time.
Inspecting and Replacing Wear Parts:
Periodic inspection and replacement is essential for components that will wear. To avoid costly downtime, we recommend that one set of each of the following components be kept on hand:
Hammers 
- Important to know:
- Depending on the application, hammers will be either 2-way or 4-way reversible, indicating the number of rotations possible before replacing.
- Hammers should be rotated when the cutting edge is well rounded and the machine is not at top efficiency.
- Hammers should always be replaced in factory balanced sets.
When to replace:
Replace hammers when both/all cutting edges are rounded.
Hammer Rods 
- Important to know:
As a best practice, hammer rods should be inspected each time hammers are rotated or replaced.
When to replace:
Replace hammer rods once they become grooved.
Screens and Bar Grates
- Important to know:
Screens (or bar grates) 
are a key factor in determining finished particle size.
When to replace:
Replace screens or bar grates when the perforations become elongated (screens) or bar edges become rounded (grates).
Wear Plates
- Important to know:
Wear plates are common on equipment processing hard /and or abrasive materials. These replaceable components protect the mill housing, extending the life of the machine.
When to replace:
Replace wear plates when they show signs of thinning. Earliest signs of thinning will be seen around the bolts.
Bearings
- Important to know:
Bearings carry the load of the rotor and can wear out over time. It is recommended that they be replaced in pairs.
When to replace:
Replace bearings if they give off excessive heat, the outer ring begins to spin, the bearing shows signs of vibrations within its housing, or if the bearing emits unusual whines or squeaks.
