FED-STD-791 Lubricants, Liquid Fuels, And Related Products, Testing Method OfThis test method standard is composed of standard test methods for sampling, inspecting and testing lubricants, liquid fuels and related products. It is issued pursuant to the Federal Property and Administration Services Act of 1949, as amended and its application to the purchase of commodities referred to herein is mandatory on all Federal agencies.

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'�NOTE:This draft dated 15 April 2006' by DasH - Page 31 of 460

FED-STD-791D

6.1.1 Preparation and cleaning of gears.

6.1.1.1 Clean, dry, and weigh test gears as follows:

a. Scrub test gears, using stiff-bristle brush and dry cleaning solvent (see Note 1).

b. Rinse gears in petroleum ether, and dry in oven at 71�C (160�F) (see Note 1).

NOTE 1:

CAUTION. Dry-cleaning solvent and petroleum ether are both toxic and

flammable. Use only in a well ventilated area. Do not breathe their fumes or

allow them to come in contact with the skin. Keep all flames from the solvent,

especially the petroleum ether.

c. Remove gears from oven, cool, and record the weight (to the nearest 0.1 mg) at

the brass gear.

6.2 Assemble the test setup as follows:

a. Mount brass gear on drive shaft and steel gear on driven shaft of the gear wear

tester (see Figure 1). Insure proper positioning of the test gears by lining up the

scribe marks (see 6.1).

b. Using flexible cord wound around the pulleys, couple the drive shaft to the

reciprocating drive mechanisms and apply a 2.27-kg (5-lb) weight to the driven

shaft.

6.3 Perform gear break-in run as follows:

a. Place container (see 4.8) under the gears, and fill it with di-2 ethylhexylsebacate

until the lower teeth of the steel gear are immersed.

b. Start the reciprocating drive mechanism, and allow it to operate for 1500

complete cycles.

c. After the test period, remove, clean, and dry the gears, and reweigh the brass gear

(see paragraph 6.1.1.1).

d. Retain the gear set for use in testing if loss in weight of brass gear does not

exceed 2.0 mg; discard (as defective) both gears of the set if loss exceeds 2.0 mg.

A drop feed lubricator has been found effective to insure removal of wear debris

NOTE 2:

during break-in run for the tests.

6.4 Assemble the test setup (paragraph 6.2) and throughly coat the gear teeth with the

grease to be tested. Then start the reciprocating drive mechanism, and allow it to operate for

6000 cycles.

6.5 At the end of the test run, remove the gears, clean and dry them, and reweigh the

brass gear as described in paragraph 6.1.1.1.