MIL-DTL-3849C
4.6.3 Physical inspections.
4.6.3.1 Breaking load (see 3.7.1 or 3.7.1.1). The finished cords shall be tested as specified in
FED-STD-228, method 3211 and shall meet the requirements of 3.7.1or 3.7.1.1 as applicable. The
following details shall apply:
a.
Each specimen shall be 1 foot in length, cut from the sample unit.
b.
Each test specimen shall be the whole cable.
c.
The test specimens shall be subjected to the tensile strength test only.
d.
The breaking load of the test specimens shall meet the requirements of 3.7.1 or 3.7.1.1 as
applicable.
4.6.3.2 Cold bend (see 3.7.2). Each specimen for the cold bend test shall be divided into two parts,
one for checking the finished (jacketed) cord as a whole, and the other for checking the insulated
conductors apart from the finished cord. After completion of the cold bend tests specified in 4.6.3.2.1 and
4.6.3.2.2, the jacketed specimens and the insulated conductor specimens shall meet the requirements
cold bend test specified in 3.7.2.
4.6.3.2.1 Cold bend (Jacketed cord) (see 3.7.2). The specimens selected for checking the cord as a
whole shall be attached to the proper size mandrel, as specified in table VI and tested as follows:
TABLE VI. Mandrel sizes for cold bend tests.
Outside diameter of
Outside diameter of
specimen in inches
mandrel in inches
(mm)
(mm)
0.000 to 0.090
.0625
(0.00 to 2.29 mm)
(15.888)
0.091 to 0.125
.09375
(3.31 to 3.18 mm)
(2.3812)
0.126 to 0.180
.125
(3.20 to 4.57 mm)
(3.18)
0.181 to 0.240
.25
(4.60 to 6.10 mm)
(6.4)
0.241 to 0.300
.375
(6.12 to 7.62 mm)
(9.53)
0.301 to 0.360
.500
(7.65 to 9.14 mm)
(12.70)
a. The specimens shall be suspended vertically with lower ends weighted sufficiently to keep
specimens taut and to permit bending them without handling.
b. The mandrels and specimens shall be placed in the cold chamber for at least 20 hours at the
temperature specified on the applicable specification sheet (see 3.1).
c. While at this temperature, the specimens shall be bent for 5 close turns around the mandrel at
the rate of approximately 1 turn per second.
d. After the test has been completed, the jacket shall be examined through a magnifying glass of
at least 3X magnification for cracks, flaws, or other damage.
e. The jacket shall then be removed, and the insulation beneath the jacket shall be examined as
specified in step d above.
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