How to Tie a Loop in Steel Cable: Wire Rope Clips, Swage & Splice Methods

Forming a permanent loop at the end of a steel cable is essential for creating anchor points, tensioning lines, and attaching hardware. There are four reliable methods — wire rope clips, swaged sleeves, mechanical splices, and hand-tucked splices — each suited to different cable sizes, load requirements, and tool availability. This guide covers all four with step-by-step instructions.

Method Comparison

When to Use a Thimble

For any loop that will be under load or attached to a hook, clevis, or shackle, install a wire rope thimble inside the loop. A thimble is a grooved metal insert that protects the cable from crushing against the hardware. Without a thimble, the cable flattens at the bearing point, which reduces strength and causes premature fatigue failure.

Rule of thumb: Use a thimble for any loop that will see more than 10% of the cable’s rated breaking strength, or any loop that will be repeatedly connected and disconnected from hardware.

Method 1: Wire Rope Clips (U-Bolt Clips)

The most common method for forming a loop in steel cable. Wire rope clips use a U-bolt, a saddle, and two nuts to clamp the cable back onto itself.

Step-by-Step: How to Install Wire Rope Clips

1. Form the loop — Pass the cable end around the thimble (if used) and bring the tail back alongside the standing line.
2. Determine the number of clips — Use the “clip rule”: number of clips = cable diameter in inches × 3 (e.g., 1/4″ cable needs 3 clips; 3/8″ cable needs 4 clips). Minimum 2 clips for any loop.
3. Space the clips evenly — Clip spacing = 6 × cable diameter. For 1/4″ cable, space clips 1.5″ apart. Measure from the center of each clip.
4. Install the first clip — Place the clip nearest the loop (the “live end” clip) first. The U-bolt goes over the dead end (the short tail). The saddle goes on the live end (the long standing line). Tighten nuts evenly.
5. Install remaining clips — Space evenly toward the tail end. All U-bolts on the dead end. All saddles on the live end.
6. Tighten to torque — Tighten nuts alternately to the recommended torque (see table below).
7. Re-tighten after initial load — Wire rope clips settle after the first load cycle. Always re-tighten to torque after the cable has been loaded once.

Wire Rope Clip Torque Specifications

Method 2: Swaged Sleeve (Nicopress)

Swaging uses an oval metal sleeve that is compressed onto the cable with a special tool. This method produces a clean, permanent loop with near-100% strength retention — the strongest termination available for small-diameter cable.

Step-by-Step: Swaging a Loop

1. Cut the cable cleanly — Use cable cutters, not bolt cutters or hacksaws, which can fray the end.
2. Slide the sleeve onto the cable — Choose a sleeve that matches the cable diameter exactly.
3. Form the loop — Wrap the cable around the thimble or fitting and insert the tail back through the sleeve.
4. Position the sleeve — The sleeve should sit 2–3 mm from the loop end, with the tail protruding 5–10 mm past the sleeve.
5. Swage the sleeve — Use a manual Nicopress tool or hydraulic swager. Make the first crimp at the center of the sleeve, then work outward in both directions. Each tool specifies the number of crimps required.
6. Measure the crimped sleeve — Use a go/no-go gauge or caliper to verify the crimped dimension matches the tool’s specification. An under-crimped sleeve can slip; an over-crimped sleeve can damage the cable.

Method 3: Mechanical Wire Rope Fittings

Mechanical fittings (also called wire rope clips, screw-on fittings, or cable ferrule ends) thread or clamp onto the cable end without requiring swaging tools.

• Threaded cone fittings — The cable end is inserted into a cone-shaped cavity, wedged with split cones, and the fitting is tightened. Common for rigging and architectural cable work.
• Set-screw fittings — The cable passes through a barrel with set screws that clamp against the strands. Quick to install but lower holding strength. Best for light-duty applications.

Method 4: Hand-Tucked Splice

The traditional method used by riggers — tucking individual strands back into the cable body to form a permanent loop. A hand-tucked splice retains 85–95% of the cable’s rated strength and is the most elegant solution for large-diameter cables where hardware would be bulky.

1. Tape the cable end to prevent fraying.
2. Unlay the strands for approximately 12–15 inches.
3. Form the loop around the thimble and lay the strands back along the standing line.
4. Tuck each strand over one strand and under the next, working around the cable. Repeat for 3–5 full tucks per strand.
5. Trim and hammer — Cut the excess strand tails and hammer the splice flat for a smooth finish.

Hand-tucked splices require practice and are generally done by professional riggers. For most DIY and industrial applications, wire rope clips or swaged sleeves are more practical.

Load Testing and Safety

Regardless of the method used, follow these safety guidelines:

• Never exceed the rated breaking strength of the cable. A loop termination reduces the cable’s effective strength by 5–20%, depending on the method.
• Apply a 5:1 safety factor for general use — the working load limit should be no more than 20% of the cable’s breaking strength.
• Use a 10:1 safety factor for overhead lifting or applications where failure could cause injury.
• Inspect loops regularly — Check for cable wear at the thimble, corrosion at the clip or sleeve, and any strand breakage.
• Test each loop after installation by applying a load equal to the expected working load before putting it into service.

Which Method Should You Use?

• DIY / farm / general outdoor — Wire rope clips (U-bolt). Easy to install, tools are just wrenches.
• Marine / coastal — Swaged sleeve with 316 stainless steel cable and sleeve. The most corrosion-resistant permanent termination.
• Aircraft / racing / safety-critical — Swaged sleeve with Nicopress tool and go/no-go gauge. Strength is verified by crimp dimension.
• Architectural / decorative — Mechanical fittings (threaded cone). Clean appearance with no exposed hardware.
• Heavy rigging / large cable — Hand-tucked splice by a professional rigger. Strongest for large-diameter cable.

Related: How to Tie Steel Cable · 304 vs 316 Stainless Steel · Stainless Steel Cable Tie Installation