MIL-DTL-24643C
4.8.6.5 Further procedure. The mandrel shall be secured to a fixed surface, one end of the specimen shall be
secured such that it is both in contact with the curved surface of the mandrel and perpendicular to the mandrel center
of the curvature axis. The opposite end of the specimen shall be bent circumferentially around the curved mandrel
surface through an arc of not less than 170 degrees. Bending shall be accomplished at the rate of approximately 20
degrees per second. The specimen shall then be secured to maintain its bent shape (as with a piece of twine,
stretched taut and tied between each end of the specimen) and shall be removed from the mandrel. Not less than two
thirds of the bent portion of the specimen shall then be dissected; each of its constituent components shall be
visually inspected for deterioration.
4.8.6.6 Further observation. Specimen failure shall be construed if the specimen, upon dissection and
inspection, exhibits visible deterioration of such a nature or extent as to impair the performance of the cable in
service. Deterioration sufficient to constitute specimen failure shall include, but is not limited to, distortion or
cracking of any constituent component, hardening of filler material or any discoloration indicating material
incompatibility.
4.8.7 Cable sealant removability. This test shall determine whether or not filler materials can be readily
removed from the constituent components of cable. This test shall not apply to filler material used to fill voids
between either conductor strands or braid strands.
4.8.7.1 Specimen. The specimen shall be a 2 foot ±2 inch length of completed cable.
4.8.7.2 Procedure. Overall specimen components (such as armors, jackets, overall binders, or shields) shall be
removed from one end of the specimen for a distance of not less than 10 inches, thereby exposing the cable core.
Using fingers only, sealant material shall then be removed from all exposed insulated conductors or from all
groupings of insulated conductors which have a common covering (such as insulated conductor pairs or triads,
which have an overall shield or binder) for a distance of not less than 8 inches. Tools, cloths, or solvents shall not
be used to assist with sealant removal. The common covering and sealant material shall then be removed from not
less than one grouping of insulated conductors, on specimens incorporating such groupings, for distance of not less
than 5 inches. Fingers only shall then be used for sealant removal. If occasional particles of sealant material remain
on any constituent component of the cable core, then the removal of these particles shall be attempted by means of
light brushing with fingers or with a dry cloth.
4.8.7.3 Observation. Any of the following shall constitute specimen failure:
a.
Sealant material is nonflexible.
b. Sealant material which adheres to the finger or to any component of the cable core. The adherence of
occasional small particles of sealant material to the cable core is acceptable unless there are small particles which
cannot be removed from the core components by light brushing with fingers or a dry cloth.
c.
Sealant material which leaves a residue on cable core components.
d.
Sealant material cannot be removed in less than 5 minutes.
4.8.8 Cold bending cable. This test shall determine the ability of completed cable, which is not intended to be
flexed during use, to withstand bending at reduced temperature, such as might be encountered during shipboard
construction or repair.
4.8.8.1 Specimen. The specimen shall consist of a piece of completed cable which shall have a length of not
less than the sum of 12 inches plus 1.6 times the specified mandrel diameter (see 3.1).
4.8.8.2 Special apparatus. Apparatus shall include the following:
a. Refrigeration chamber shall support the requirements as specified in 4.8.8.3. The chamber air temperature
shall be measured in the immediate vicinity of the specimen.
b. Mandrel shall be rigid, smooth cylinder or partial cylinder, with a continuous, curved surface of not less
than 180 degrees, of suitable length and construction for the specimen bending of 4.8.8.3. Unless otherwise
specified (see 3.1), the mandrel diameter shall be a maximum of 13 times the diameter of the cable. The mandrel
shall be provided with a clip for affixing one specimen end (see 4.8.8.3).
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