MIL-DTL-12713E
temperature shall be raised gradually to +145 ± 5°F. The quadrant shall remain at this
temperature for a minimum of 4 hours. At the completion of this 4 hour period, and within
10 minutes of removal from the environmental chamber, the quadrant shall again meet
requirements listed in 3.3.2. Upon completion of this test, the quadrant shall be returned to
the environmental chamber and the temperature shall be gradually reduced to room
ambient temperature (+60°F to +90°F) at which time the quadrant shall be removed from
the test chamber. The same units may be used for both storage temperature and operating
temperature verifications, if desired. (See 6.7 Thermal shock.)
4.5 End-for-end. The end-for-end correction is the reading shown on the gunner's
quadrant when it can be placed on a level surface in two opposing directions that both
result in a level vial bubble that is centered within the width of a graduation line. This
correction shall not be greater than the tolerance specified. (See 6.6 for suggested test
method.)
4.6 Micrometer. Zero the index arm and micrometer of the gunner's quadrant.
Place the quadrant on an adjustable elevation fixture and adjust the fixture to center the
level vial bubble of the gunner's quadrant. Remove the gunner's quadrant from the fixture,
set the index arm to -10 mils, set the micrometer to 10 mils, and place the gunner's
quadrant back on the elevation fixture in the same orientation. Without adjusting the
elevation fixture, the level vial bubble shall be centered within the tolerance specified.
4.7 High angle shoes. Adjust the elevation angle test fixture to 800 mils elevation.
Place the gunner's quadrant on the fixture using the low angle shoes, adjust the quadrant to
center the level vial bubble, and record the elevation as read from the gunner's quadrant.
Without adjusting the elevation angle test fixture, remove the gunner's quadrant, set to 800
mils elevation on the high angle scale, and then replace it on the fixture using the high
angle shoes. Adjust the quadrant to center the level vial bubble, and record the elevation as
read from the gunner's quadrant. The difference between the recorded elevation for the
low angle shoes at 800 mils and the recorded elevation for the high angle shoes at 800 mils
shall be within the tolerance specified.
4.8 Accuracy. Set a calibrated inspection aid to zero mils elevation then position it
on the seat provided on the elevation angle test fixture. Adjust the test fixture until the
inspection aid level vial bubble is centralized when the elevation angle test fixture is set for
zero mils elevation. Set the quadrant under test to zero mils elevation and place it on the
seat provided on the test fixture in the same position as the inspection aid. Adjust the
gunner's quadrant micrometer until the level vial bubble is centered within a level vial
graduation line. If a negative correction is necessary, lower the quadrant's index arm 10
mils and then use the micrometer to center the level vial bubble. The difference between
the actual elevation and the elevation indicated by the gunner's quadrant is the amount of
error at that elevation. The error shall not be greater than the tolerance specified in 3.7.
In addition, accuracy shall be tested at a minimum of 4 diversified angles of
elevation while on the low angle shoes of the quadrant (e.g. 200, 400, 600, and 800 mils)
and a minimum of 4 diversified angles of elevation while on the high angle shoes of the
quadrant (e.g. 800, 1000, 1200, and 1400 mils). This is accomplished by checking the
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