FED-STD-791D
4.1.8.5 Emergency stop. The emergency stop button (Figure 6, item 26) on the
console stops the driver 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.
4.1.8.6 Scuff rating equipment. A microscope and a light source are used for
visual inspection of the narrow test gear. An optional closed circuit television camera
and monitor (Figure 6, item 4) may be used for inspection of the narrow test gear. To
inspect the narrow gear, the machine is first stopped. The inspection can then be made
through special inspection holes provided in the gear-case end cover. These holes are
closed by corks during the test run.
4.1.8.7 Inspection equipment. The standard 18X microscope furnished with the
Erdco Ryder gear machine, or equivalent, is slightly modified by the addition of a
supplementary lens in the right objective-lens opening. The right eyepiece of the
microscope contains a net reticule that divides the gear-tooth area lengthwise into seven
sections. The grid lines provide a convenient means for the visual estimation of the
percent of gear-tooth area that has been scuffed.
4.1.8.8 Gear-tooth indexing ratchet. An indexing ratchet is normally used for
rotating the test gears so that the teeth of the narrow test gear can be inspected
individually. If the optional closed circuit television camera and monitor are used, a
television antenna rotor may be adapted to engage the output shaft of the step-up gearbox
and provide the rotation of the narrow test gear for remote inspection.
4.1.8.9 Additional instruments:
a. Stop watch for oil flow-rate check.
b. Micrometer 0 to 2.5 cm (0 to 1 in) for the measurement of the gross tooth width
of the narrow gear.
c. Scale with divisions of 0.04 cm (1/64 in).
d. Set of conventional mechanical tools as necessary for assembly, disassembly,
maintenance, and repair.
4.2 Test gear plating procedure.
4.2.1 The following procedure is used to plate the black chromium rings on the
web of the narrow test gears:
1. Clean the gear with dry-cleaning solvent and rinse with petroleum ether.
2. Mask the area to be plated with masking tape. (The area to be plated includes
the flat area on both sides of the narrow test gear between the root diameter of
the gear teeth and the OD of the test gear hub, not including the fillet.)
3. Place the gear in a wire holder and immerse in hot platers wax. Dip the gear
successively until the wax has formed a coating approximately 0.32 cm (1/8 in)
thick on all gear surfaces.
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