along a line, the twist is to the right. During construction
of natural fiber line, a lubricant is added that also serves
as a preservative.
Large line is measured by circumference. Line 1
3/4 inches and under in circumference, called small
stuff, is identified by the number of threads in the line. A
line with twenty-four thread is 1 1/2 inches in
circumference. Inasmuch as the numbers of threads per
strand are equal, thread numbers in a three-strand line
are divisible by 3—24, 21, 18, and so on, down to the
smallest—6 thread (3/4 inch). Line from 1 3/4 inches to
about 4 inches is manufactured in 1/4-inch graduations.
The length of all line and wire rope is usually measured
in feet.
The chart shown below lists tips on the care of
natural fiber line. You should be thoroughly familiar
with them and observe them at all times.
NYLON LINE
Most of the tips for the care of natural fiber line
should be observed with nylon line. Nylon, however, is
not subject to mildew. It should be scrubbed if it
becomes slippery because of oil or grease.
A stretch of one third of its length is normal for
nylon line under safe working loads. Nylon stretches
about 50 percent before it will break. Because of its
elasticity, nylon line breaks with a decided snapback;
therefore, stand well clear when it is under a heavy
strain.
7-13
Student Notes:
NEVER
ALWAYS
Stow wet or damp line in an unventilated
compartment or cover it so that it cannot dry. Mildew
will form and weaken the fibers.
Dry line before stowing it.
Subject line to intense heat nor unnecessarily allow it
to lie in the hot sun. The lubricant (natural oils) will
dry out, thus shortening the useful life of the line.
Protect line from weather when possible.
Subject a line to loads exceeding its safe working
load. To do so may not break the line, but individual
fibers will break, reducing the strength.
Use chafing gear (canvas, short lengths of old firehose,
and so on) where line (or wire) runs over sharp edges or
rough surfaces.
Allow line to bear on sharp edges or run over rough
surfaces. The line will be cut or worn, reducing the
strength and useful life.
Slack off taut lines when it rains. Wet line shrinks, and
if the line is taut, the resulting strain may be enough to
break some of the fibers.
Scrub line. The lubricant will be washed away, and
caustics in strong soap may harm the fibers.
Coil right-laid line to the right (clockwise).
Put a strain on a line with a kink in it.
Inspect a line before using it. Overworked or
overstrained line will have a bristly surface. Mildew
can be seen, and it has peculiar, unpleasant odor.
Untwist the line so that the inner parts of the strands
can be seen. If they have a dull, grayish look, the line is
unsafe.
Try to lubricate line. The lubricant you add may do
more harm than good.
Give line the care it deserves—someday your safety
may depend on it.
