4.6.4 Humidity. This test shall be conducted in accordance
with method 507.1, procedure IV defined in MIL-STD-810. During
each test measurement period shown on figure 507.1-3, the scale
shall be inspected for physical damage and shall be tested in
accordance with 4.6.10 to determine operability in compliance with
3.11. Upon completion of this test, the scale shall be subjected
to the tests specified in 4.6.5 and shall conform to the
requirements referenced therein.
4.6.5 Post-environmental. Subsequent to the tests specified
in 4.6.2 and 4.6.4 the scale shall be subjected to a visual and
tactile examination for defects or damage as specified in 3.6.
The scale shall then be subjected to the tests specified in 4.6.6
to 4.6.10 inclusive, and shall conform to the requirements
4.6.6 Printing and surface quality. This test consists of a
visual examination of the face of the scale for imperfections of
coloring applications, letters, numbers, surface quality, stains
and other imperfections in accordance with the requirements of
4.6.7 Scales. All scales shall be visually inspected for
quality of printed graduations and to insure that colors are in
accordance with pertinent drawings in compliance with the require-
ments of 3.8. The graduations shall then be inspected for
accuracy of divisions and subdivisions by being subjected to the
test specified in 4.6.3 and shall conform to the requirements
4.6.8 Graduation error - "C" and "D" scales. Determine
graduation error between the "C" and "D" scales by utilizing
standard measuring equipment capable of measuring any misalignment
of the scale graduations within the tolerance specified. Move the
center slide until the index of the "C" scale is in coincidence
with the index of the "D" scale and clamp the slide and the rule.
together lightly to prevent movement. Each graduation on the "C"
scale shall be checked for alignment with the opposite graduation
on the "D" scale within the tolerance specified in 3.9.1.
188.8.131.52 Accuracy. - ratio "C" and "D" scales. To determine
the ratio of 2/3 for the "C" scale with respect to the "D" scales,
utilize the same set up as specified in 4.6.8. Align the index of
the "C" scale opposite the "15" graduation line of the "D" scale
and clamp the slide and rule together lightly to prevent movement.
At this setting, a ratio of 2/3 shall be read throughout the scale
with the opposite graduations in alignment within the tolerance
specified in 3.9.2.