FED-STD-791D
switch on the console remains in the "close" position. For this reason, the switch should
be turned to the "open" position prior to the next run.
4.2.5 Emergency stop. The emergency stop button (Figure 2, item 18) on the
console stops the drive motor and turns off all the controls except those for instruments.
The timer switch and the load bypass switch remain in the positions to which they were
originally set.
4.3 Scuff rating equipment. A microscope and a light source for visual
inspection of the narrow test gear are provided as standard equipment with the Ryder
gear-Erdco universal tester. A camera with accessories for photographing the gear teeth
is available as optional equipment. To inspect or photograph the narrow test gear the
machine is stopped, but the test oil is kept circulating through the bypass circuit. The
inspection or photographing can then be accomplished through special inspection holes
provided in the gear case without taking off the end cover. These holes are closed with
corks during the test run.
4.4 Inspection equipment. The microscope provided with the tester is an 18X
stereoscopic microscope. A high intensity light source is provided for use with the
microscope. Figure 8 shows the inspection equipment in position for use. The left
eyepiece of the microscope contains a net reticule which divides the gear tooth area
lengthwise into five 20%-sections as shown in Figure 10. These 20% grids provide a
convenient means for the visual estimation of the percentage of gear tooth area that has
been scuffed. Scuffing of individual gear teeth is estimated to the nearest 5%.
4.5 Photographic equipment. This is optional equipment consisting of a Leica
camera with a copying attachment, a viewer, and an electronic flash unit synchronized
with the camera shutter. Figure 9 shows this equipment installed for use.
4.6 Gear tooth indexing rachet. An indexing rachet (Figures 1 and 8) is used to
rotate the test gears so that the teeth of the narrow gear can be brought into position one
by one for inspection or photography.
4.7 Additional instruments.
a. Stop watch for measurement of test oil flow rate.
b. Micrometer 0. to 2.5 cm (0 to 1 in) for measurement of the gross tooth width of
the narrow test gear.
c. Set of conventional mechanical tools as necessary for assembly, disassembly,
maintenance and repair.
5. MATERIALS
5.1 CAUTION: SOME MATERIALS ARE TOXIC AND HAZARDOUS. The
materials references and standards listed in this section must be handled carefully.
Federal Test Method 10000, Material Handling Safety Precautions, is a reference which
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