depending on what purpose the wire rope is intended.
Wire rope is designated by the number of strands per
rope and the number of wires per strand. Thus a
1/2-inch 6 by 19 wire rope has six strands with
19 wires per strand. It has the same outside diameter
as a 1/2-inch 6 by 37 wire rope that has six strands with
37 wires (of smaller size) per strand.
The design arrangement of a strand is called the
construction. The wires in the strand may be all the
same size or a mixture of sizes. The most common
strand constructions are Ordinary, Scale, Warrington,
and Filler (fig. 5-2).
. Ordinary construction wires are all the same size.
. Scale is where larger diameter wires are used on
the outside of the strand to resist abrasion and smaller
wires are inside to provide flexibility.
l Warrington is where alternate wires are large and
small to combine great flexibility with resistance to
l Filler is where small wires fill in the valleys
between the outer and inner rows of wires to provide
good abrasion and fatigue resistance.
The wire rope core supports the strands laid
around it. The three types of wire rope cores are fiber,
wire strand, and independent wire rope (fig. 5-3).
. A fiber core maybe a hard fiber, such as manila,
hemp, plastic, paper, or sisal. The fiber core offers the
advantage of increased flexibility. It also serves as a
Figure 5-3.Core construction.
cushion to reduce the effects of sudden strain and act as
an oil reservoir to lubricate the wire and strands (to
reduce friction). Wire rope with a fiber core is used
when flexibility of the rope is important.
. A wire strand core resists more heat than a fiber
core and also adds about 15 percent to the strength of
the rope; however, the wire strand core makes the wire
rope less flexible than a fiber core.
. An independent wire rope core is a separate wire
rope over which the main strands of the rope are laid.
This core strengthens the rope, provides support against
crushing, and supplies maximum resistance to heat.
When an inspection discloses any unsatisfactory
conditions in a line, ensure the line is destroyed or cut
into small pieces as soon as possible. This precaution
prevents the defective line from being used for
Wire rope may be manufactured by either of two
methods. When the strands or wires are shaped to
conform to the curvature of the finished rope before
laying up, the rope is termed preformed wire rope.
Figure 5-2.Common strand construction.