Expert Guide to How to Join Steel Wire Rope: 3 Proven Methods Compared (2025)

Abstract

The structural integrity of a steel wire rope termination is a foundational determinant of safety and efficacy in lifting and rigging operations. An improper joining method can catastrophically compromise the rope's load-bearing capacity, often leading to failure at a fraction of its nominal breaking strength. This document provides a comprehensive examination of three principal methodologies for creating terminations in steel wire rope: mechanical splicing through swaging, the application of wire rope clips, and the traditional practice of hand-tucked splicing. It analyzes the underlying mechanical principles, procedural requisites, and operational contexts for each technique. The investigation weighs the relative merits of each approach, comparing their resultant termination efficiencies, requirements for specialized equipment and operator skill, and suitability for field versus workshop environments. The objective is to furnish a lucid, comparative framework, enabling engineers, riggers, and technicians to make informed, safety-conscious decisions when selecting the appropriate procedure for how to join steel wire rope for a given application.

Key Takeaways

• Mechanical swaging creates a strong, permanent termination but requires specialized hydraulic presses.
• Wire rope clips offer adjustable, field-installable solutions, though with lower efficiency ratings.
• Hand-splicing is a traditional skill that produces a flexible eye without reducing rope diameter.
• The method you choose to join steel wire rope directly impacts its final breaking strength.
• Always follow the "never saddle a dead horse" rule when installing U-bolt type wire rope clips.
• Termination efficiency can range from 80% for clips to over 95% for professionally swaged sleeves.
• Regular inspection of all rope joints for wear, slippage, or corrosion is vital for safety.

Table of Contents

• Understanding the Foundation: Steel Wire Rope Anatomy
• Method 1: Mechanical Splicing (Swaging) for Permanent Connections
• Method 2: Wire Rope Clips for Adjustable and Field Terminations
• Method 3: The Art of Hand-Tucking for a Traditional Eye Splice
• Comparing the Methods: Efficiency, Application, and Skill
• Safety, Inspection, and Load Capacity Considerations
• Frequently Asked Questions (FAQ)
• A Final Word on Responsibility and Craft
• References

Understanding the Foundation: Steel Wire Rope Anatomy

Before one can truly grasp the nuances of how to join steel wire rope, a foundational appreciation for its intricate structure is necessary. A steel wire rope is not a monolithic entity; it is a complex machine composed of numerous moving parts designed to work in concert. Imagine it not as a simple cord, but as a collection of high-strength steel wires meticulously twisted into strands, which are then helically laid around a central core. The performance of any joint or termination depends entirely on how it interacts with this sophisticated architecture.

The core serves as the heart of the rope, providing support for the outer strands. It maintains their relative positions under load, preventing the rope from crushing and deforming. Cores typically fall into two categories: fiber cores (FC) and steel cores. A fiber core, often made of natural materials like sisal or synthetic polymers like polypropylene, offers flexibility and retains lubricant, which it gradually releases to reduce internal friction and corrosion among the wire strands. An independent wire rope core (IWRC), conversely, is a smaller wire rope in its own right, situated at the center of the larger rope. An IWRC provides superior strength, greater resistance to crushing on a drum, and higher tolerance for heat compared to a fiber core. The choice between them depends entirely on the rope’s intended application—flexibility versus raw strength and durability.

The strands are the next layer of this mechanical onion. Each strand is a helical arrangement of individual steel wires. The number of wires per strand and the number of strands in the rope define its classification. For example, a common 6×19 classification rope contains 6 strands, with each strand composed of 19 wires. This construction offers a good balance of abrasion resistance and fatigue resistance. A 6×37 rope, with more wires per strand, would be more flexible but more susceptible to surface wear.

Finally, we consider the "lay" of the rope. The lay describes the direction in which the wires are twisted to form the strands, plus the direction the strands are twisted around the core. In a Regular Lay rope, the wires in the strand are twisted in one direction, while the strands themselves are laid around the core in the opposite direction. This configuration provides good stability and crush resistance. In a Lang Lay rope, both the wires and the strands are twisted in the same direction. A lang lay rope offers excellent fatigue resistance and flexibility, making it suitable for applications with a lot of bending over sheaves, but it is more prone to untwisting. Understanding these components—core, strands, and lay—is not merely academic; it is the bedrock upon which safe and effective rigging is built. Any method used to join steel wire rope must respect and properly engage these elements to maintain structural integrity.

Method 1: Mechanical Splicing (Swaging) for Permanent Connections

Mechanical splicing, commonly known as swaging or pressing, represents a modern, highly reliable method for forming a permanent eye or termination on a steel wire rope. The process involves deforming a soft metal sleeve, or ferrule, around the rope using immense pressure. The resulting connection is clean, compact, and, when performed correctly, can achieve an efficiency that rivals the strength of the rope itself. Think of it as a form of cold forging, where the ferrule material flows into the valleys between the rope's strands, creating an incredibly secure mechanical and frictional bond.

The Principle of Swaging

At its core, swaging is a masterful application of material science. The ferrules are typically made from aluminum, copper, or steel, with each material chosen for specific applications. Aluminum is the most common for its excellent ductility and corrosion resistance, making it ideal for galvanized and stainless steel wire ropes. Copper is often used for its superior performance in certain corrosive environments, while steel sleeves are reserved for applications demanding the highest strength and abrasion resistance, often used on un-galvanized bright wire rope.

When a swaging press applies force, the ferrule material is compressed beyond its elastic limit. It behaves almost like a fluid, flowing into the interstitial spaces between the individual wires and strands of the rope. This action does not merely squeeze the rope; it creates an intimate, form-fitting lock. The pressure is so great that the ferrule and the rope become a single, integrated unit. A properly swaged termination secures the rope through a combination of this mechanical interlock and the immense frictional forces generated by the compression. The resulting eye termination is permanent—it cannot be disassembled without destroying the ferrule.

Tools and Materials

Achieving a secure swaged termination is impossible without the correct tools and materials. The quality of the joint is directly proportional to the quality of the components used.

• Swaging Tool (Press): These tools generate the force needed to deform the ferrule. For smaller diameter ropes (typically up to about 8-10 mm), hand-operated swaging tools with long lever arms may suffice. These are portable and useful for field repairs or smaller projects. For larger ropes and for industrial or critical lifting applications, a hydraulic press is non-negotiable. These presses can generate hundreds of tons of force, ensuring the ferrule metal flows completely and uniformly. They use specialized die sets that match the exact size of the ferrule being pressed. Using incorrect dies is a recipe for a failed termination.
• Ferrules (Sleeves): These are the metal sleeves that are pressed onto the rope. They come in various shapes, with the simple oval shape being the most common for forming an eye. Duplex or "figure-8" sleeves are used for lap splices, joining two ropes end-to-end (a practice generally discouraged for overhead lifting). It is absolutely vital that the ferrule material is compatible with the wire rope material to prevent galvanic corrosion, and its size must precisely match the rope's diameter.
• Thimbles: A thimble is a grooved metal protector placed inside the loop of the eye. Its purpose is to protect the rope from abrasion and maintain the eye's shape. When a rope bends around a sharp object or a pin, the outer wires are put under immense strain while the inner ones are compressed. A thimble provides a smooth, correctly-sized radius for the rope to bend around, distributing the load evenly and drastically increasing the life of the termination. Using an eye without a thimble, especially in applications with dynamic loading or connection to hardware, is poor practice.

Step-by-Step Swaging Process

Executing a proper swage requires precision and adherence to manufacturer specifications. The process is not forgiving of shortcuts.

1. Preparation: First, the wire rope must be cut cleanly to the desired length. An abrasive cutting wheel is preferred over shears, as shears can crush the end of the rope and make it difficult to insert into the ferrule. After cutting, select the correct size ferrule and thimble for the rope diameter.
2. Assembly: Pass the end of the wire rope through the ferrule. Then, guide the rope around the thimble, ensuring it sits snugly in the thimble's groove. Insert the end of the rope—the "dead end"—back into the ferrule alongside the "live end" (the load-bearing part of the rope). A small tail of the dead end, approximately one rope diameter in length, should protrude from the ferrule. This visual indicator helps confirm that the rope has not slipped during the pressing operation.
3. Positioning and Pressing: Place the assembled ferrule and rope into the correctly sized die set within the swaging tool. The placement is important; manufacturers provide guidelines on the number of presses required and their locations along the length of the ferrule. For a standard oval sleeve, multiple presses are often required, starting from the end nearest the eye and working towards the rope's tail. This sequence pushes any excess material towards the tail rather than trapping it.
4. Gauging and Inspection: After pressing, the process is not complete. A "go/no-go" gauge must be used. This is a simple tool with a slot that corresponds to the correct final diameter of the swaged ferrule. If the swaged ferrule passes through the "go" side but stops at the "no-go" side, the press is successful. If it is too small (over-swaged) or too large (under-swaged), the termination is compromised and must be cut out and redone. A visual inspection should also check for any cracks in the ferrule or excessive "flash" (metal squeezed out between the dies), which can indicate improper pressure or worn dies.

Advantages and Limitations of Swaged Terminations

Swaging is a favored method in professional rigging for several reasons. Its primary advantage is strength and efficiency. A properly executed swage can achieve a termination efficiency of 95-100%, meaning the connection is as strong or nearly as strong as the rope itself. The resulting termination is smooth, compact, and less likely to snag than a clipped termination.

However, the method has its limitations. The primary drawback is the requirement for specialized, often expensive, equipment. The process is also irreversible; a mistake cannot be undone without cutting the termination off and starting over, which consumes both rope and materials. This makes it less suitable for applications requiring on-the-fly adjustments or temporary installations. The skill required, while less artisanal than hand-splicing, still demands meticulous attention to detail and a thorough understanding of the equipment and specifications. A casual approach to swaging can create a termination that looks secure but is, in fact, dangerously weak.

Method 2: Wire Rope Clips for Adjustable and Field Terminations

When a permanent, factory-pressed termination is impractical or undesirable, wire rope clips provide a robust and field-installable alternative for forming an eye. These devices function by clamping two sections of the rope together—the live end and the dead end—using bolts to generate immense clamping force. This method is exceptionally useful for creating terminations on-site, for applications where the length may need to be adjusted, or for temporary rigging setups. While they offer great utility, their effectiveness is entirely dependent on correct installation. Unlike a swaged ferrule, where the process is largely governed by the machine, the integrity of a clipped termination rests squarely in the hands of the installer.

The Mechanics of Friction and Grip

The principle behind a wire rope clip is straightforward: friction. The clips create a high-pressure connection that prevents the dead end of the rope from slipping past the live end when a load is applied. The design of the clip is intended to achieve this grip without causing excessive damage to the wire rope. An improperly installed clip can crush the rope, creating a weak point that fails well below the rope's rated capacity. The number of clips, the torque applied to the nuts, and the spacing between clips are all calculated to provide sufficient frictional force to hold the full working load limit of the rope. It is a balancing act between gripping the rope securely and preserving the structure of its wires and strands.

Types of Wire Rope Clips

There are two primary designs of wire rope clips, each with distinct features and proper use cases.

• U-Bolt Clips: This is the most common type. It consists of a U-shaped bolt, a saddle, and two nuts. The saddle is the component that is grooved to match the rope's texture. The U-bolt provides the clamping force when the nuts are tightened. Because of their asymmetrical design, their orientation is of paramount safety importance. They are widely available and cost-effective.
• Fist Grip Clips (Double-Saddle Clips): These clips use two identical, grooved saddles clamped together by two bolts. Because both saddles are designed to contact the rope, there is no "wrong" way to orient them, which eliminates the primary installation risk associated with U-bolt clips. They generally provide a more uniform clamping force, causing less potential damage to the rope. However, they are typically more expensive and bulkier than their U-bolt counterparts.

The "Never Saddle a Dead Horse" Rule

This phrase is perhaps the most important safety mnemonic in all of rigging. It applies specifically to the installation of U-bolt clips. The "saddle" is the grooved, forged part of the clip. The "dead horse" refers to the dead end of the wire rope—the short tail end that does not carry the load. The rule dictates that the saddle of the clip must always be placed on the live end of the rope, while the U-bolt goes on the dead end.

Why is this so important? The saddle is designed to support the rope and distribute the clamping force across its surface. The U-bolt, with its tighter radius, concentrates the pressure. Placing the U-bolt on the live, load-bearing end of the rope will crush the wires, severely weakening it at that point. Under load, these crushed wires can fail, causing the entire termination to slip or break. A correctly installed clip places the primary gripping force on the live end via the saddle, while the potentially damaging U-bolt is placed on the non-load-bearing dead end. Adherence to this rule is not optional; it is fundamental to the safety of the termination.

Step-by-Step Guide to Applying Wire Rope Clips

Correct application involves more than just getting the orientation right. Spacing, turn-back length, and torque are all specified by manufacturers and standards bodies like the American Society of Mechanical Engineers (ASME).

1. Determine Specifications: Before starting, consult a manufacturer's chart or a reliable rigging handbook (Lift-It, 2025). You will need to know the required number of clips, the amount of rope to turn back, the spacing between clips, and the correct torque value for the nuts. These values are specific to the rope's diameter.
2. Prepare the Eye: Form the eye by turning back the specified length of rope from the thimble.
3. Attach the First Clip: Apply the first clip at the "throat" of the loop, as close to the thimble as possible. Place the saddle on the live end and the U-bolt on the dead end. Tighten the nuts, but do not apply the final torque yet. The clip should be snug enough to hold the thimble in place.
4. Attach the Remaining Clips: Place the second clip as near to the end of the dead end as possible. Do not clamp it down yet. If more than two clips are required, space them evenly between the first and last clips. The minimum spacing is typically six times the rope diameter.
5. Apply Tension and Torque: Apply a light tension to the sling assembly to take up slack. Now, begin to tighten the nuts on all clips. Alternate between the nuts on a single clip to ensure even pressure. Use a torque wrench to tighten all nuts to the manufacturer's recommended value. It is vital to tighten the clip furthest from the eye first, then the one nearest the eye, and finally the clips in between. This sequence helps to distribute the tension properly.
6. Re-Torque After Initial Loading: The most overlooked step is re-torquing. After the first load is applied to the assembly, the rope will stretch and settle, causing the clips to loosen. The nuts on all clips must be re-tightened to the specified torque. This should also be part of a regular inspection schedule.

Common Mistakes and Safety Concerns

The utility of wire rope clips is matched by their potential for misuse. A termination made with clips is only as good as its installation.

• Incorrect Orientation: Reversing the U-bolt clip ("saddling a dead horse") is the most dangerous error, as it damages the live end of the rope.
• Improper Torque: Under-tightening will allow the rope to slip under load. Over-tightening can crush and damage the rope wires, creating a hidden weak point. A calibrated torque wrench is not a luxury; it is a necessity.
• Incorrect Spacing or Number of Clips: Using too few clips or placing them too close together will not provide enough frictional grip to hold the rated load. Always follow the manufacturer's specifications.
• Mismatched Components: Never use clips from one manufacturer with saddles or U-bolts from another. They are not designed to work together. Likewise, never use clips on plastic-coated wire rope unless the coating is stripped where the clips will be placed, as the plastic will deform and allow the rope to slip.

Wire rope clip terminations are rated at an efficiency of about 80% when installed correctly. This means a rope with a breaking strength of 10,000 pounds will have a termination breaking strength of only 8,000 pounds. This reduction must be factored into all safe load calculations.

Method 3: The Art of Hand-Tucking for a Traditional Eye Splice

Long before the invention of hydraulic presses and forged clips, riggers joined steel wire rope using nothing more than their hands and a few simple tools. The hand-tucked splice, or eye splice, is a testament to the craft and ingenuity of traditional rigging. It involves unlaying the strands at the end of a rope and weaving them back into the body of the rope to form a secure eye. The result is a tapered, flexible termination that is often considered more art than science. While less common in modern industrial settings due to the time and skill required, it remains an invaluable technique in certain fields, particularly in marine applications and for specialized .

The Theory Behind the Hand Splice

A hand splice does not rely on compression like a swaged sleeve or on clamping force like a clip. Instead, it secures the rope by distributing the load through pure friction, achieved by the intricate weaving of the strands. When the eye of a spliced rope is put under tension, the helical lay of the main body of the rope tightens. This "constrictor" effect grips the tucked strands, and the friction generated between the core, the tucked strands, and the standing strands becomes immense. A properly executed splice creates a frictional lock so strong that the rope will often break in its body before the splice gives way.

The process involves a sequence of "tucks," where each of the unlaid strands is passed over one standing strand and under another. A standard splice for a six-strand rope typically requires a minimum of five full tucks for each of the six strands. The first tuck is the most demanding, as it establishes the pattern and brings all six strands into the body of the rope. Subsequent tucks build upon the first, creating the elongated, tapered connection that is the hallmark of a hand splice.

Essential Tools for Hand-Splicing

While the method relies on manual dexterity, a few specialized tools are indispensable for manipulating high-strength steel wires.

• Marlinspike: This is the primary tool. It is a tapered steel pin, sometimes slightly curved, used to open a space between the strands of the wire rope. The end of a tucking strand is then passed through this opening. A spike that is too small will not create enough space, while one that is too large can deform the rope.
• Wire Cutters: Heavy-duty cutters are needed to trim the excess from the strands after the tucks are complete.
• Serving Mallet and Wire: After the splice is finished, the tapered end is often "served" or "whipped." This involves tightly wrapping the splice with annealed wire to prevent the cut ends of the strands from snagging and to give the splice a clean, finished appearance. A serving mallet helps to wrap the wire tightly and uniformly.
• Vise: A sturdy bench vise is needed to hold the wire rope securely during the splicing process, freeing up both of the rigger's hands.

The Basic 5-Tuck Splice: A Detailed Walkthrough

Describing a hand splice in text is like trying to teach someone to tie a knot over the phone—it is a tactile, three-dimensional process. However, we can outline the fundamental sequence. Let's imagine we are splicing a standard 6-strand, right-lay wire rope.

1. Unlaying the Strands: First, the end of the rope is served with wire to prevent it from unlaying completely. Then, a length of rope needed for the splice (roughly 30 times the rope diameter) is carefully unlaid into its six individual strands and its core. The core is cut off short. The ends of each of the six strands are also served to prevent them from fraying.
2. Forming the Eye and the First Tuck: The unlaid strands are bent back to form an eye of the desired size, often around a thimble. Now comes the most pivotal part. The six loose strands must be inserted into the body of the rope. Using the marlinspike, the rigger pries open a space under one strand of the main rope body. The first loose strand is tucked through this opening, against the lay of the rope. This is repeated for all six strands, creating a pattern where each strand goes under one standing strand.
3. Subsequent Tucks: For the second tuck and beyond, each strand is woven in a pattern of "over one, under one." The strand is passed over the standing strand adjacent to the one it just went under, and then tucked under the next one after that. This over-under sequence is what creates the interwoven lock.
4. Completing the Splice: This process is repeated until each of the six strands has been tucked at least five times. For extra security or to create a smoother taper, some of the wires within each strand can be trimmed after the third tuck, and the remaining wires tucked two more times. After all tucks are complete, the excess ends of the strands are hammered down and the splice is served with wire for a tidy and snag-free finish.

When to Choose a Hand Splice

In an age of hydraulic efficiency, why would anyone choose such a labor-intensive method? The hand splice offers unique advantages. A key benefit is flexibility. The splice remains as flexible as the rope itself, making it ideal for running rigging that must pass over sheaves or for slings that need to conform to irregular loads. The tapered end also passes smoothly without snagging, a useful feature for towing or choker applications. Furthermore, a hand splice can be visually inspected for broken wires or slippage in a way that a swaged sleeve, which conceals the rope, cannot.

The disadvantages, however, are significant. The process is extremely time-consuming and requires a high level of skill and practice. An improperly tucked splice is exceptionally dangerous, as it can unravel under load. The efficiency of a hand splice is also generally lower than that of a swaged termination, typically ranging from 75% to 90% depending on the rope's construction and the splicer's skill. This method has largely been replaced in high-volume production but remains a cherished and sometimes necessary skill in specialized corners of the rigging world (Cranebriefing.com, 2024).

Comparing the Methods: Efficiency, Application, and Skill

Choosing how to join steel wire rope is not a matter of selecting the "best" method, but rather the most appropriate one for the task at hand. Each technique—swaging, clipping, and hand-tucking—presents a different balance of strength, cost, convenience, and required expertise. A decision made without considering these factors can lead to inefficiency at best and catastrophic failure at worst.

Termination Efficiency is the most critical safety metric. It represents the strength of the finished termination as a percentage of the rope's own nominal breaking strength (HHI Lifting, 2024). A swaged sleeve, when properly applied, is the undisputed leader, creating a joint that is virtually as strong as the rope. Wire rope clips are the weakest, typically derating the rope's capacity by 20%. This is because their clamping action, even when correct, slightly deforms and stresses the rope's wires. The efficiency of a hand splice is highly variable and depends entirely on the skill of the rigger and the construction of the rope.

Application and Serviceability also present a clear trade-off. Swaging is ideal for the mass production of high-quality slings and assemblies in a workshop setting but is ill-suited for on-site adjustments. Wire rope clips are the opposite; they are the go-to solution for field work, allowing for adjustments and disassembly. Imagine setting up temporary guy lines for a tower; clips allow you to tension the lines perfectly on-site. A hand splice offers a middle ground; it can be done in the field without heavy machinery, but it is far too slow for rapid or temporary work.

Skill and Cost are the final pieces of the puzzle. Hand-splicing is an art form that takes years to master, making the labor cost per termination very high. Swaging requires a significant upfront investment in a press but allows for rapid, repeatable production with a moderately skilled operator who can follow a procedure. Wire rope clips require the least expensive tools, but the "skill" required is one of meticulousness and adherence to rules. The low tool cost can create a false sense of simplicity, making it the method most prone to catastrophic failure from installer error. The decision of how to join steel wire rope is therefore an engineering choice, balancing the demands of the job with the resources and expertise available.

Safety, Inspection, and Load Capacity Considerations

Regardless of the method chosen for how to join steel wire rope, safety remains the paramount concern. The termination point is statistically one of the most likely places for a rigging assembly to fail. This failure is rarely due to a defect in the rope itself but is almost always a result of an improperly made or poorly maintained connection. A deep understanding of load capacity reduction, inspection criteria, and regulatory guidelines is not just good practice—it is an ethical obligation for anyone involved in lifting and rigging.

How Joints Affect Working Load Limit (WLL)

Every wire rope has a Nominal Breaking Strength (NBS) provided by the manufacturer. However, a rope should never be used at this load. Instead, a Working Load Limit (WLL) is calculated by dividing the NBS by a Design Factor (also called a Safety Factor). This factor, typically 5:1 for lifting applications as per ASME standards, accounts for dynamic forces, wear, and other variables (Rigging Canada, 2025). For example, a rope with an NBS of 50,000 pounds and a 5:1 design factor has a WLL of 10,000 pounds.

Crucially, the termination's efficiency rating must be applied to this calculation. The WLL of the entire assembly is limited by its weakest component, which is often the termination.

• If using a swaged sleeve with 95% efficiency, the assembly's WLL would be: (50,000 lbs / 5) * 0.95 = 9,500 lbs.
• If using wire rope clips with 80% efficiency, the assembly's WLL drops to: (50,000 lbs / 5) * 0.80 = 8,000 lbs.

Ignoring the termination efficiency factor is a dangerous oversight that effectively overloads the connection from its very first use.

Inspecting Your Wire Rope Connections

A termination is not a "fit-and-forget" component. Regular and thorough inspection is the primary defense against failure. An inspector should be trained to look for specific warning signs at the termination point.

• For All Types: Look for broken wires at the point where the rope enters the fitting. This is a high-stress area, and wire breaks here are a clear indicator of fatigue or overload. General corrosion is also a major red flag, as it can hide more severe internal damage.
• Swaged Terminations: Check the ferrule for any cracks, which indicate a faulty press or material defect. Look for any sign of the rope slipping out of the sleeve—this is visible if the dead end tail is no longer protruding or has pulled into the ferrule.
• Clipped Terminations: These require the most diligent inspection. Verify that the clips are correctly oriented ("saddle on the live end"). Check for slippage, which can be identified by marks or distortion on the rope. Most importantly, re-check the nut torque. Clips will loosen after initial loading and with vibration, and regular re-torquing is a mandatory part of any maintenance schedule.
• Hand-Tucked Splices: Inspect the splice for any tucked strands that have started to pull out or unlay. Look for broken wires, particularly at the point of the first tuck where stresses are highest. Severe corrosion within the splice is difficult to detect visually but can be a concern in marine environments.

Any termination showing these signs should be immediately removed from service. The cost of replacing a sling or remaking a termination is insignificant compared to the potential cost of an accident.

Regulatory Standards and Best Practices

Professional rigging is governed by strict standards to ensure safety and interoperability. In the United States, OSHA (Occupational Safety and Health Administration) regulations and ASME (American Society of Mechanical Engineers) standards are paramount. Specifically, ASME B30.9, "Slings," provides detailed requirements for the fabrication, attachment, use, inspection, and maintenance of all types of lifting slings, including those made from wire rope. These standards dictate everything from the minimum number of wire rope clips to the design factor for a given application. Adhering to these standards is not only a legal requirement in many jurisdictions but also a fundamental best practice that embodies the collective experience and wisdom of the entire lifting industry.

Frequently Asked Questions (FAQ)

Which method of joining steel wire rope is the strongest?

When performed to manufacturer and industry standards, a properly swaged mechanical splice is the strongest method, typically achieving 95% to 100% of the rope's original breaking strength. Hand-tucked splices come next, with efficiencies between 75% and 90%, followed by wire rope clips, which are rated at 80% efficiency for U-bolt types.

Can I use knots to join steel wire rope?

Absolutely not. Tying a knot in wire rope is extremely dangerous and severely compromises its strength. A knot creates a very tight bend radius that puts immense stress on the outer wires, crushing them and creating a significant weak point. A simple overhand knot can reduce a wire rope's strength by 50% or more, leading to unexpected failure under a load far below its rating.

How often should I inspect my wire rope terminations?

Inspection frequency depends on the service conditions. According to ASME B30.9, a visual inspection should be performed before each use or each shift for slings in regular service. A more thorough, documented inspection by a qualified person should occur periodically, with the interval depending on the severity of use—annually for normal service, and more frequently (monthly to quarterly) for severe service.

Why is the rule "never saddle a dead horse" so important for U-bolt clips?

This rule is critical because it ensures the live, load-bearing part of the wire rope is supported by the forged saddle of the clip, which distributes clamping force evenly. The U-bolt, which concentrates pressure, is placed on the non-load-bearing "dead end." Reversing this ("saddling the dead horse") puts the crushing force of the U-bolt directly onto the live end, damaging the wires and creating a point of failure that can cause the termination to slip or break under load.

Is it possible to join two pieces of wire rope end-to-end for lifting?

While it is technically possible using multiple clips or special lap-splicing sleeves, joining two ropes end-to-end to make a longer rope is strongly discouraged for any overhead lifting application. Each joint introduces a potential point of failure. The preferred and safer practice is to use a single, continuous piece of wire rope of the appropriate length for the task. Lap splices are more commonly seen in non-critical applications like guardrails or temporary pulling setups.

Can I reuse wire rope clips?

Yes, wire rope clips are generally reusable, provided they pass a thorough inspection. Before reuse, check the clips for any signs of damage, such as cracking, deformation, or significant corrosion. The threads on the U-bolt and nuts must be clean and undamaged to ensure proper torquing. Never reuse a clip that shows any signs of distortion or excessive wear.

What is the purpose of a thimble in a wire rope eye?

A thimble is a metal liner placed inside the eye of a termination. Its primary function is to protect the rope from wear and crushing. It provides a larger, smoother bending radius when the eye is connected to other rigging hardware like hooks or shackles. This prevents the rope from making a sharp bend, which would weaken it, and protects the individual wires from abrasion, significantly extending the service life of the termination.

A Final Word on Responsibility and Craft

The act of joining a steel wire rope transcends mere mechanical procedure; it is an exercise in responsibility. Whether pressing a ferrule with a multi-ton hydraulic machine, meticulously torquing the nuts on a series of clips, or weaving strands with a marlinspike, the rigger is creating a connection upon which property, and potentially lives, will depend. Each method carries with it a distinct legacy—the industrial precision of the swage, the field-ready utility of the clip, and the artisanal heritage of the hand splice. The selection of a method is not a casual choice but an informed decision, one that weighs the demands of the load against the integrity of the connection. The knowledge of how to join steel wire rope is, therefore, a craft rooted in a deep respect for the materials, a commitment to procedural discipline, and an unwavering dedication to the safety of the operation.

References

Cranebriefing.com. (2024, May 16). The key to safe sling selection. Crane Briefing. https://www.cranebriefing.com/news/the-key-to-safe-sling-selection/8037296.article

HHI Lifting. (2024, December 30). Chain sling securement: Mastering the essentials for safe lifting. https://www.hhilifting.com/en/news/post/chain-sling-securement-mastering-the-essentials-for-safe-lifting

Juli Sling Co., Ltd. (2025). Steel wire rope. Juli Sling. https://julislings.com/steel-wire-rope-category/

Lift-It Manufacturing, Inc. (2025). Wire rope sling tag requirements, considerations & removal from service criteria. Lift-It.

Rigging Canada. (2025). Rigging terms glossary. Rigging Canada.