Wire Rope Rigging Terms: The Complete Glossary (With Clip Chart)

Rigging has its own language, and getting a word wrong can mean getting the wrong rope, the wrong sling or the wrong hitch. This guide covers the wire rope and rigging terms crews use every day: how wire rope is built, how strength is rated, the fittings and hitches, and the inspection words that mean a rope comes out of service.

Elko Wire Rope has supplied riggers across Utah, Nevada and Arizona for more than 30 years from our branches in Salt Lake City, Elko, Phoenix and Safford. If a term here doesn't answer your question, ask us.

What is wire rope?

Wire rope is steel wires twisted into strands, and strands laid around a core. That layered build lets it carry heavy tension while still bending over sheaves and drums. It's used for crane hoist lines, winch lines, guy lines and, cut and terminated, for wire rope slings.

Wire rope anatomy

• Wire: the smallest piece. High-carbon steel drawn to size.
• Strand: a group of wires laid around a center wire.
• Core: the center the strands are laid around. It supports the strands and keeps the rope round.
• IWRC (independent wire rope core): a small wire rope used as the core. Strongest and most crush-resistant.
• FC (fiber core): polypropylene or natural fiber. More flexible, weaker, not for heat.
• WSC (wire strand core): a single strand as the core, common in small-diameter rope.
• Diameter: measured across the widest points of the strands (crown to crown), never flat to flat.

Construction and lay

• Construction: strands × wires per strand, such as 6x19 or 6x37. The first number is the strand count; the second is the approximate wires per strand. See 6x19 vs 6x37 and IWRC vs fiber core.
• Class: a family of constructions with similar strength and weight. "6x19 class" includes 6x19 Seale, 6x25 Filler Wire and 6x26 Warrington Seale.
• Lay (direction): right lay strands spiral like a right-hand thread; left lay the opposite. Right lay is standard.
• Regular lay: wires twist opposite to the strands. Easier to handle, resists crushing and kinking. The standard.
• Lang lay: wires twist the same way as the strands. More wear and fatigue resistant, but must be held at both ends or it unlays.
• Lay length: the distance along the rope for one strand to make a full turn. Inspection counts broken wires within one or more lay lengths.
• Rotation-resistant rope: layered strands laid in opposite directions so the rope resists spinning under load. Used on cranes lifting single-part loads.
• Compacted strand: strands pressed smooth for more steel in the same diameter, more strength and better wear.
• Preformed: wires and strands shaped before laying so the rope doesn't spring apart when cut. Nearly all rope today is preformed.

Grades and finishes

• IPS: improved plow steel, the base strength grade.
• EIPS (XIP): extra improved plow steel, about 15% stronger than IPS. The common grade for slings.
• EEIPS (XXIP): extra extra improved plow steel, about 10% stronger than EIPS.
• Bright: uncoated rope, kept lubricated.
• Galvanized: zinc-coated for corrosion resistance, at slightly lower strength in most grades.

Strength and load terms

• Minimum breaking strength (MBS): the load the rope or sling is certified to hold before breaking. Never a working number.
• Design factor: MBS divided by the rated load. 5:1 for wire rope slings, higher for some hoisting applications.
• Working load limit (WLL) / rated capacity: the most you may lift, in a specific hitch. It's on the sling tag. See our wire rope sling capacity chart.
• Shock load: a sudden load, like a jerk or a dropped-and-caught load, that can far exceed the static weight.
• D/d ratio: the diameter of the sheave, pin or object the rope bends around (D) divided by the rope diameter (d). Smaller ratios mean tighter bends and less strength and life.
• Center of gravity: the point where the load balances. Rig above it or the load tips.

Terminations and fittings

• Eye: a loop formed at the end of the rope.
• Thimble: a grooved metal insert that protects the eye from wear and tight bending.
• Flemish eye: an eye formed by splitting and re-laying the rope, then securing it with a pressed sleeve. The standard for sling eyes.
• Mechanical (pressed) splice / swaged sleeve: a metal sleeve pressed over the rope to hold the eye. Strong and consistent.
• Hand-tucked splice: an eye spliced by hand without a sleeve. Rated lower than a mechanical splice.
• Wedge socket: a field-installable end fitting where the rope wraps a wedge that tightens under load. Common on crane hoist lines.
• Wire rope clip (U-bolt clip): a U-bolt and saddle used to form a temporary eye. The saddle goes on the live (loaded) end: "never saddle a dead horse."
• Turnback: the length of rope folded back to form a clipped eye.

Wire rope clips: how many you need

Typical minimums for forged wire rope clips on right regular lay rope. Always follow the clip manufacturer's instructions and torque the nuts to their spec, then re-torque after the first load.

Slings and hitches

• Sling: a length of rope, chain or synthetic webbing with fittings, used to attach a load to a hook. Wire rope slings come single-leg or as 2-leg, 3-leg and 4-leg bridles.
• Bridle: a multi-leg sling joined at a master link.
• Vertical hitch: the sling hangs straight from the hook to a single point. The baseline rating.
• Choker hitch: the sling wraps the load and passes through its own eye, tightening as it lifts. Rated at about 75% of vertical.
• Basket hitch: the sling cradles the load with both eyes on the hook. Up to twice vertical when the legs are vertical.
• Sling angle: the angle between a leg and the horizontal. Flatter angles put more load on each leg. See how lifting angles affect sling capacity.
• Round sling: an endless synthetic sling, color coded by capacity. See the round sling color chart.

Rigging hardware

• Shackle: a U-shaped connector closed by a pin. Bow and D shapes, screw pin or bolt type. See our shackle guide and WLL chart.
• Master link: the oblong link at the top of a bridle that goes on the hook.
• Hook latch: the spring gate that keeps a sling from jumping off a hook.
• Spreader or lifting beam: a below-the-hook beam that holds sling legs apart, reducing angle loads or protecting the load.
• Tag line: a hand line on the load used to control swing. Never wrapped around a hand.
• Hoist: a device that lifts using chain or rope, such as a hand chain hoist or lever hoist.

Inspection and damage terms

• Broken wires: the main removal criterion. Limits depend on the application; for wire rope slings, ASME B30.9 removes a sling with 10 randomly broken wires in one rope lay or 5 broken wires in one strand in one rope lay.
• Birdcage: strands opened up like a cage, usually from shock unloading or twisting. Remove from service.
• Kink: a permanent sharp bend from a loop pulled tight. Remove from service.
• Crushing / flattening: rope pressed out of round on a drum or by a load. Remove from service.
• Core protrusion: the core pushing out between strands. Remove from service.
• Heat damage: discoloration, weld spatter or arc strikes. Remove from service.
• Reduced diameter: wear or internal failure. Compare to the original diameter.
• Qualified person: someone who, by knowledge, training and experience, can solve rigging problems and make inspection calls.

For what each kind of damage looks like and why it happens, see common wire rope sling failures, and use the rigging equipment checklist before every lift.

Talk to a rigger

Elko Wire Rope builds wire rope slings to spec and stocks crane rope, shackles and rigging hardware at all four branches. Tell us the load and the job, and we'll get you the right gear.

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Wire Rope Terminology FAQs

What is the difference between wire rope and cable?

In practice people use both words. In the trade, "cable" usually means small-diameter rope, roughly 3/8" and under, and "wire rope" means anything larger.

What does "never saddle a dead horse" mean?

When installing wire rope clips, the saddle goes on the live (load-bearing) end of the rope and the U-bolt on the dead (short) end. Reversed clips crush the live rope and can hold far less.

Which wire rope has wires and strands twisted in the same direction?

Lang lay. In regular lay, the wires twist the opposite way to the strands.

What's the difference between rigging and lifting?

Rigging is everything that connects the load to the hoist: slings, shackles, hooks, spreader beams and how they're arranged. Lifting is moving the load.

How do you measure wire rope diameter?

With calipers across the widest points of opposite strands (crown to crown). Measuring flat to flat reads small.