MIL-DTL-3432J
TABLE XIX. Computed mandrel size.
Mandrel size, maximum
Nominal outside diameter
of insulated conductor or
Unshielded cable
Shielded cable
Individual insulated conductors
1/
cable, inclusive
Inch (mm)
Inch (mm)
Inch (mm)
Inch (mm)
Up to .150(3.81)
1.0(25.4) x OD
3.0(76.2) x OD
1.0(25.4) x OD
.151(3.84) to .250(6.35)
1.0(25.4) x OD
3.0(76.2) x OD
1.5(38.1) x OD
.251(6.38) to .300(7.62)
1.0(25.4) x OD
3.0(76.2) x OD
2.0(50.8) x OD
.301(7.65) to .350(8.89)
2.0(50.8) x OD
3.0(76.2) x OD
2.0(50.8) x OD
.351(8.92) to .450(11.4)
2.5(63.5) x OD
3.0(76.2) x OD
2.5(63.5) x OD
.451(11.5) to .550(14)
3.0(76.2) x OD
3.0(76.2) x OD
3.0(76.2) x OD
.551(14) to .750(19)
4.0(102) x OD
4.0(102) x OD
.751(19) to .950(24.1)
5.0(127) x OD
5.0(127) x OD
.951(24.2) to 1.500(38.1)
6.0(152) x OD
6.0(152) x OD
1.501(38.1) to 2.00(50.8)
8.0(203) x OD
8.0(203) x OD
2.001(51.1) and over
10.0(254) x OD
10.0(254) x OD
1/ For the nominal outside diameter cable (see 1.2.1.7). The nominal outside diameter of the insulated conductor
shall be determined from the nominal outside diameter of the conductor and the nominal insulation thickness (see
table VI). For parallel cables, the nominal outside diameter shall be the major axis.
4.7.9 Marking durability. A short specimen of finished wire or sheath shall be firmly clamped in a horizontal
position with its upper longitudinal surface area freely exposed. A small steel mandrel.025 inch diameter (0.625mm)
±.001 inch (.0254mm) shall be repeatedly rubbed over the insulation surface at the stripe so that the longitudinal axis
of the mandrel and specimen will be at right angles to each other. A weight shall be affixed to the jig holding the
rubbing mandrel so that the combined jig and weight exerts a 500-gram thrust normal to the insulation surface. A
motor-driven reciprocating cam mechanism and counter shall be used to permit an accurately measured number of
abrasion strokes. The length of stroke in one direction shall be .375 inch (9.53mm) and the frequency of strokes shall
be 120 strokes per minute (each stroke consisting of a 180° rotation of the eccentric drive mechanism). The direction
of motion shall be along the axis of the wire or cable jacket and perpendicular to the axis of the mandrel. This
procedure shall be repeated on one additional specimen selected at least 50 feet away from the previous specimen.
4.7.10 Polyethylene shrink-back. A 7-inch long specimen shall be cut from the insulated conductor. Shield and
color coding braid, tape, or jacket shall be removed. The specimen shall then be cut to 6 inches (152.4mm) with the
conductor flush with the insulation. The specimen shall then be air oven aged at 85± 1°C for 24 hours ± .5 hour. The
specimen shall then be removed and allowed to cool to room temperature. The amount the conductor extends
beyond the insulation shall be measured at each end and the insulation shall be examined for splitting or cracking.
4.7.11 Polyamide heat stability.
4.7.11.1 Polyamide coating over the primary insulation. A 1-foot specimen shall be bent around a metal mandrel
six times the outside diameter of the specimen for two turns and taped down on its ends. The specimen and the
mandrel shall be placed in a gravity convection type oven at a temperature of 93.3± 2.9°C for 24 hours. Remove the
specimen and mandrel from the oven and cool them in a silica gel desiccator or equivalent until they return to room
temperature (1 hour minimum). Remove them from the desiccator, straighten the specimen and inspect for tears or
cracks in the material.
4.7.11.2 Polyamide coating under or over component shield. A sufficient length of specimen shall be used to
ensure at least six close turns when bent on a metal mandrel, six times the outside diameter of the specimen. Each
turn shall be in contact with the next. The ends of the specimen shall be taped together so that the turns are held in
place on the mandrel. The mandrel and specimen shall be suspended in a gravity convection oven at the
temperature of 148.9± 2.8°C for 15 minutes. The specimen and mandrel shall be removed from the oven and cooled
in a silica gel desiccator or equivalent until the specimen is at room temperature (1 hour minimum). Remove them
from the desiccator, unwrap the coils, and inspect for tears or cracks in the material.
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