MIL-DTL-48557B
requirements in accordance with 3.4.5. Fixture 11747196 may be used to adapt the mount
to the vibration test equipment. Upon completion of the vibration test, the mount shall be
examined and inspected to meet the requirements of 3.5 through 3.11 inclusive.
4.5 Locating keys for M137A2 telescope. Install the mount on holding fixture,
11747950, and place a parallel bar across the locating keys for the M137A2 telescope. Use
a dial indicator across the parallel bar to verify compliance with the requirements of 3.5.
4.6 Mounting surfaces of M17A1 quadrant. Install the mount on holding fixture,
11747950, and use a dial indicator across the mounting surfaces for the M17A1 quadrant
(bolt hole locations) to verify compliance with the requirements of 3.6.
4.7 Performance. Test fixture, 10555619, equipped with inspection aide support
assembly, 10553898, and with fixture adapter, 13042935, or functional equivalent shall be
used for the inspection of M171A1 mount. Position the test fixture on a vibration free
surface in accordance with the set-up instructions outlined on drawing 10555619. Install
inspection aide support assembly in accordance with the set-up instructions outlined on
10553898. Install fixture adapter in accordance with the set-up instructions outlined on
13042935. Follow all set-up and operating instructions prior to securing the mount to the
fixture. Verifications shall be done with the starting position of the mount as follows:
a. The mounting surface (internal surface) of the mount shall be in a vertical plane
within 1.0 mils.
b. The locating keyway of the mount shall be in a horizontal plane within 10
seconds.
c. The four mounting bolts shall be torqued to 85 to 90 foot pounds.
d. The top locating surface for the M137A2 telescope shall be parallel to the
locating keyway of the mount within 0.5 mils.
e. The elevation and cross level vial bubbles shall be centered within the thickness
of a graduation line.
4.7.1 Locating keys for M17A1 quadrant. With the mount positioned as specified
in 4.7, the locating keys for the M17A1 quadrant shall be level within the tolerance
specified in 3.7.1.
4.7.2 Elevation level vial. With the mount positioned as specified in 4.7, confirm
that the mounting surface of the M137A2 telescope is level, and observe the elevation level
vial bubble is centered within the width of a level vial graduation line to confirm
conformance with 3.7.2.
4.7.3 Elevation adjustment range. With the mount positioned as specified in 4.7
and with the leveling adapter, 10558253-11, attached, rotate the fixture to elevate and
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