National Crane Published 08/16/19 Control # 112-05 6-7
500E2 SERVICE MANUAL SWING
plating that will cause variation from dry torque values. When
a high strength bolt is removed, or un-torqued, the bolt must
be replaced with a new bolt of the same classification.
Torque the capscrews to recommended values, refer to
Fasteners and Torque Values, page 1-7.
NOTE: Zinc flake coated bearing bolt heads are stamped
with the suffix “ZF” as a visual identifier.
KNOW YOUR TORQUE WRENCH! Flexible beam type
wrenches, even though they might have a pre-set feature,
must be pulled at right angle and the force must be applied at
the center of the handle. Force value readings must be made
while the tool is in motion. Rigid handle type, with torque
limiting devices that can be pre-set to required values,
eliminate dial readings and provide more reliable, less
variable readings.
NOTE: If multipliers and/or special tools are used to reach
hard to get at areas, ensure torque readings are
accurate.
Torque wrenches are precision instruments and must be
handled with care. To ensure accuracy, calibrations must be
made on a scheduled basis. Whenever there is a possibility
that a torque wrench may have been either overstressed or
damaged, it should immediately be removed from service
until re-calibrated. When using a torque wrench, any erratic
or jerking motion can result in the application of excessive or
improper torque. ALWAYS use a slow, even movement and
STOP when the predetermined value has been reached.
If it is reported by the crane operator or suspected that the
crane has been overloaded beyond the capacities specified
above the bold line on the cranes’ capacity chart, then all
swing bearing bolts must be inspected for looseness and
re-torqued to specifications.
Torque the swing bearing bolts according to the procedures
outlined in this section.
When using step wrenches, calculated wrench settings are
valid only when the following conditions are met.
1. Torque wrenches must be those specified and forces
must be applied at the handle grip. The use of handle
extensions will change applied torque to the bolt.
2. All handles must be parallel to the step wrench during
final tightening. Multiplier reaction bars may be
misaligned no more than 30 degrees without causing
serious error in torque.
3. Multiplier bar handles must be propped or supported
within the outer 1/4 of the handle length, or serious
under or over tightening will occur.
Swing Bearing Bolts
The inner race of the bearing is secured to the turret by 26
capscrews (Figure 6-1). The outer race of the bearing is
secured to the frame by 24 capscrews (Figure 6-1).
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