Wire Rope Clips & Wedge Sockets

The end of a wire rope has to be finished with a termination so it can be attached to a hook, a shackle or an anchor. Two common field terminations are U-bolt wire rope clips and wedge sockets. Both work well when installed correctly, and both fail dangerously when they’re installed backward, with too few clips, or not torqued.

• Rigging
• Cranes
• Construction

Terminations reduce rope strength

• Any termination makes the rope weaker than its rated breaking strength. A properly made clip termination is generally about 80 percent as strong as the rope. A wedge socket is often rated at about 80 percent as well, and a swaged or poured socket is stronger.
• Use the manufacturer’s efficiency rating when calculating the working load. Never exceed the rated load for the termination.
• Clips are often used for temporary lines and tie-downs. They shouldn’t be used for permanent lifting slings or in places where a failure could drop a load on people, unless the standard and the maker allow it.

U-bolt wire rope clips

A U-bolt clip has a U-shaped bolt and a saddle (the base). Rope is doubled back to form an eye, and clips hold the two parts together.

The golden rule: never saddle a dead horse

• The saddle goes on the live end (the loaded part of the rope).
• The U-bolt goes on the dead end (the short tail).
• Remember: “Never saddle a dead horse.” Putting the saddle on the dead end puts the U-bolt against the live rope, crushes and kinks it, and cuts its strength.

How many clips, and how far apart

• OSHA’s rigging standard requires that the number and spacing of clips follow Table H-2 in 29 CFR 1926.251, for U-bolt clips used to form eyes. The number of clips increases with rope diameter, for example 3 clips for smaller rope and more for larger rope, and spacing is about six rope diameters.
• Follow the manufacturer’s chart, since it’s based on the clip and rope. Use drop-forged clips, not malleable cast clips, for lifting.
• Use clips sized for the rope diameter. Match the clip size to the rope.

Installing clips

1. Turn back the rope the required length (the “turnback”) and use a thimble in the eye to protect the rope from wear and kinking.
2. Place the first clip one saddle width from the dead end, with the U-bolt on the dead end, and tighten it to the specified torque.
3. Place the second clip close to the thimble, and tighten it only snug.
4. Place any middle clips spaced evenly, and take up the slack in the rope before tightening.
5. Tighten all clips to the specified torque with a torque wrench. Rope diameter and clip size determine torque, so use the maker’s table.
6. Apply a load gradually and then re-tighten all the clips, because the rope compresses. Re-check after the first few uses and regularly.

• Don’t use too few clips or space them too far apart.
• Don’t install clips staggered, with the U-bolts on opposite sides.
• Don’t use clips to splice two ropes together for lifting, or use them on a rope being used to lift people.
• Don’t tighten clips by hand without a torque wrench.

Wedge sockets

A wedge socket has a tapered body and a wedge. The rope loops around the wedge, and the load pulls the wedge tight into the socket. It lets you change a rope termination quickly in the field, such as on a crane hoist line.

• Match the socket, wedge and rope size from the manufacturer, and follow the maker’s instructions.
• Form the loop so the live end of the rope is in a straight line with the pin and the pull. The live rope must leave the socket straight in line with the direction of pull, not along the curved side.
• Leave a dead-end tail of the length the maker specifies (often at least 6 rope diameters, or at least 6 inches).
• Secure the dead end with the clip or clamp that the manufacturer calls for, attached to the tail only, not to the live rope. This prevents the wedge from backing out if the load slackens. The tail clip is not a load-bearing clip.
• Seat the wedge by applying a load to pull it tight before the first lift.
• Check regularly for wedge movement, cracks, tail length changes and wear. A change in tail length shows the wedge is slipping.
• Don’t hit the wedge with a hammer, don’t use the wrong wedge, and don’t reuse a wedge that is damaged.

For cranes, follow the crane maker’s manual and the OSHA crane rules. See Wire Rope, Crane Inspections and Crane Basics.

Inspection and care

• Inspect terminations before use: look for slipping, kinks, crushed or broken wires near the termination, corrosion, cracked or bent clips, stretched U-bolts and loose nuts.
• Wire rope removal criteria such as broken wires also apply near terminations. See Sling Inspection.
• Remove from service any termination that has been shock-loaded or damaged. Replace, don’t repair.
• Keep clips and sockets lubricated and clean, and store them dry.

Termination checklist

• Right clip or socket for the rope diameter; drop-forged clips for lifting
• Saddle on the live end; U-bolt on the dead end
• Correct number of clips and spacing from the table; thimble in the eye
• Clips torqued, loaded and re-torqued; wedge seated with correct tail length
• Efficiency of the termination used when figuring the rated load
• Terminations inspected before each use

Last updated: October 4, 2026