Chapter 8 General Reference
79
Turntable Bearing Inspection
Turntable bearings may experience wear. One of the following conditions may indicate turntable
bearing wear:
1
Metal particles present in the bearing lubricant.
2
Increased drive power required to rotate the crane.
3
Noise emitting from the bearing during rotation.
4
Rough rotation.
5
Uneven or excessive wear between the pinion gear and turntable gear.
If one or more of the above conditions exists, further inspection may be required. Limits are
measured in “TILT” which is dependent on the internal clearances of the bearing. TILT is the
most practical determination of a bearings' internal clearance once mounted on a crane. You
can measure the tilt using the
Turntable Bearing Tilt Test.
(see "Turntable Bearing Tilt Test" on
page 80)
Periodic readings indicating a steady increase in TILT may be an indicator of bearing wear.
Note: A bearing found to have no raceway cracks or other structural irregularities should be reassembled
and returned to service.
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