FED-STD-791D
9.2 Work a grease sample for 60 double strokes using the full scale grease or
one-half scale grease worker at room temperature.
9.3 Weigh an inboard and outboard bearing cone to the nearest 0.1g.
9.4 Pack a worked grease sample into the test bearings (inboard: 3.0 0.1 g.
outboard: 2.0 0.1 g) using the following bearing packing procedure: Fill the bearings
with the worked test grease using a grease packer utilized in ASTM D 3527 test method.
Use care to prevent relative rotation of rollers and bearing components while removing
the cones from cups and in all subsequent wiping and handling steps. Strike off excess
grease flush using a small spatula. Wipe all grease from cone bore, cone back face,
exterior cage surfaces and exposed roller surfaces with a clean lint free cloth or towel and
reweigh. Adjust the grease weight in the inboard and outboard cones to 3.0 and 2.0
0.1g, by wiping or adding grease to the groove between the cage and cone back face.
9.5 Clean the bearing cups installed in the hub using heptane and apply a thin
film of the test grease to the races.
9.6 Set-up a test specimen assembly according to the following procedure:
Without any rotation of the test bearing, the inboard bearing is installed on the spindle.
Then, this spindle is mounted on the test preparation stand which was designed for
holding it in a vertical position. The hub is gently set on the inboard bearing with the
torque arm aligned with the spindle set screw. (i.e., pointing in the same direction).
Then, the outboard bearing is placed on the hub. The thrust force (400 N) is applied to
the test bearings with a calibrated spring-loading device.
9.7 Prepare four test specimen assemblies using the above test assembly
preparation procedure.
9.8 Without disturbing the test assemblies, place them in an oven preheated to 70
3 C for 1 hour.
9.9 Rotate the test specimen assemblies for 1 revolution using the test apparatus
at room temperature.
9.10 Install two test specimen assemblies on each drive shaft for the first two
tests. Without any handling of the test assemblies, the torque arms should be placed
vertically with the drive motors.
9.11 Place the other two test assemblies inside the cold chamber in preparation
(cold soak) for the next tests.
9.12 Insert two thermocouples (T type) in the test spindles to monitor the test
temperature.
9.13 Start 16 hour cold-soak at -54 0.5 C.
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