There are, of course, many other types of wire rope, but they are useful only in a limited
number of applications and, as such, are sold as specialties. Usually designated according
to their actual construction, some of these special constructions are listed in Table 2 and
show in Figure 8.
WIRE ROPE INSTALLATION
CHECKING THE DIAMETER
It is most important to check the diameter of the delivered rope before installation. This is
to make certain that the rope diameter meets the specified requirements for the given
machine or equipment. With an undersize diameter rope, stresses be increased; an
oversize diameter rope will wear out prematurely. This happens because of abuse to the
rope caused by pinching in the grooves of the sheave and drum.
In checking, however, the “true” rope diameter (4) must be measure. And this is defined as
the diameter of the circumscribing circle, i.e., its largest cross-sectional dimension. To
insure accuracy this measurement should be made with a wire rope caliper using the
correct method (2) shown in Fig. 11. For measuring ropes with an odd number of outer
strands, special techniques must be employed.
Design specifications for wire rope are such that the diameter is slightly larger than the
nominal size, according to the allowable tolerances shown in Table 3.
TABLE 3
OVERSIZE LIMITS OF WIRE ROPE DIAMETERS*
Nominal Rope Diameter Allowable Limites
Thru 1/8" -0 +8%
Over 1/8" thru 3/16" -0 +7%
Over 3/16" thru 1/4" -0 +6%
Over 1/4" and larger -0 +5%
*These limits have been adopted by the Wire Rope Technical Board (WRTB), and are being
considered for inclusion in the forthcoming revised edition of "Federal Standard RR-
W-410." In the case of certain specila purpose ropes, such as aircraft cables and elevator
ropes, each has specific requirements.
RT500
Applicable Standards / Regulations
292 REVISED:
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