SLINGS

WIRE ROPE

GENERAL INFORMATION 

rope is cut in the splice area and doesn't add to the overall

A  forming tuck  is made by prying two adjacent strands

strength of the sling.  Rated capacities of slings using gal 

apart, inserting a dead end strand into the opening and

vanized rope depend on the method of galvanizing.  The

passing the strand under one, two, or three adjacent

sling manufacturer should be consulted regarding rated

strands in the body of the rope.  The dead end strand is

capacities for these types of slings.

set or locked tightly.

A  full tuck  is made by inserting a dead end strand under

and rotating in one full 360 degrees turn around and

strand in the body of the wire rope.  The tucked strand is

set or locked tightly.  Each subsequent full turn of the dead

end strand around the live end strand constitutes an addi 

tional full tuck.

 Setting  or  locking  of a dead end strand is accomplished

by pulling the strand end in under considerable force.  A

marlin spike is inverted in the same opening in the body of

the rope ahead of the tucked strand and is rotated about

the axis of the rope back to the start of the tuck.  Certain

end useages may indicate the desirability of special

splices such as the Navy Admiralty Splice or logging

splice.  Splices made by these special methods may also

attain the efficiencies used in calculating the rated capacity

MINIMUM SLING BODY LENGTH is the minimum length

tables where the rope quality and number of tucks are

of wire rope between splices, sleeves or fittings.  Generally

equivalent to that outlined above.  Development of such

the minimum body length is equal to ten (10) times the

efficiencies should be confirmed by the sling fabricators

sling body diameter.  This allows approximately one and

making such splices.

one half (1 1/2) rope lays between splices.  For multi part

slings the minimum body length between splices is equal

Serving or wrapping of wire rope sling splices does not

to forty (40) times the component rope diameter.

affect the splicing efficiencies nor rated capacities.  Such

servings are optional, although unserved splices are pre 

LENGTH TOLERANCE is generally plus or minus two (2)

ferred because they permit visual inspection of the spliced

body diameters, or plus or minus 0.5% of the sling length,

area.

whichever is greater.  The legs of bridle slings, or matched

slings are normally held to within one (1) body diameter.

NOMINAL SPLICE EFFICIENCIES are measured in terms

Tolerances on poured or swaged socket assemblies are

of efficiency (where efficiency = actual breaking strength of

generally much closer.  Tolerances should always be spec 

spliced termination divided by actual breaking strength of

ified to the sling manufacturer before the order is placed.

the rope).  The efficiency will change from splice to splice

This eliminates a lot of frustration and confusion later.

because of the many variable factors involved in producing

the splice.  Splice efficiencies given in table 3 were estab 

HAND TUCKED SPLICE

lished so that these normal variations are accommodated.

A HAND TUCKED splice is made by passing the wire rope

The design factor used in establishing the rated capacities

around a thimble or forming an eye and splicing the dead

further assures that the sling will lift the load even in those

end (short end) into the live and (long end) of the rope.

rare instances when the splice efficiency falls slightly

Normally, each dead end strand is given one forming tuck

below the values given in the tables.  Rated capacities

and three full tucks around the same strand in the body of

shown in this manual have met with the most exacting

the rope.  One additional full tuck is made when splicing

test, that of the test of time and use in over fifty years of

more pliable wire ropes such as 6X37 classification.

actual field experience.

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