Wire Rope Sling Strength and Capacity Guide (Guide)

A wire rope sling isn’t just any rope; it’s a powerhouse of strength designed to lift and move heavy stuff safely. It’s not a one-size-fits-all situation when you choose a sling. You’ve got to consider the weight you’re lifting and the environment you’re working in.

The most common wire rope slings you’ll find are the 6×19 and 6×37 types. The 6×19 wire rope slings are your go-to for strength and durability, with larger outer wires for toughness against wear and corrosion. For more flexibility, use the 6×37 slings, packed with smaller wires, making them ideal for complex lifting tasks where agility is key.

This article will delve deeper into wire rope slings, focusing on their types, safe load capacities, and minimum breaking strengths. We’ll also explore how to determine the safe load and understand the critical aspect of breaking strength for secure and efficient lifting operations.

What is Wire Rope Sling?

man in black and white gloves holding a rope

Now, imagine a bunch of steel wires, all twisted and turned together – that’s your wire rope sling. It’s not just any old rope; these things are engineered for strength.

The cool thing about wire rope slings is they’re not one-size-fits-all. They come in different designs to match what you’re lifting. It’s like having the right tool for the job.

I’ve seen them configured in all sorts of ways, each tailored for different kinds of loads. The secret sauce to their strength is how the wires are wound together. This coiling gives them their muscle, supporting hefty loads and offering top-notch stability.

Wire Rope: Safe Load, Minimum Breaking Strength, and Weight

a person is crippling wire to test breaking point

Understanding wire ropes’ strength and capacity is crucial, especially regarding safe working load (SWL), minimum breaking strength, and weight.

The SWL varies with the diameter of the wire rope sling and its weight per foot. Generally, a smaller diameter means a lower SWL. Additionally, the SWL is influenced by the safety factor ratio, which isn’t always clearly stated on the wire ropes.

To give you a clearer picture, here’s a combined table that outlines the minimum breaking strength, safe load, and weight for each wire rope diameter, along with the equivalent breaking strength for different materials and constructions.

Rope Diameter (in/mm)Minimum Breaking Strength (lbf/kN)Safe Load (lbf/kN)Weight (lbm/ft/kg/m)
1/4 / 6.45480 / 24.41100 / 4.890.11 / 0.16
5/16 / 88520 / 37.91700 / 7.560.16 / 0.24
3/8 / 9.512200 / 54.32440 / 10.90.24 / 0.36
7/16 / 11.516540 / 73.63310 / 14.70.32 / 0.48
1/2 / 1321400 / 95.24280 / 19.00.42 / 0.63

In most wire rope cores, which typically comprise six strands with 15–66 wires each, the greater the wire count, the stronger the strand.

To aid in selecting the right wire rope, here’s a table showing the equivalent breaking strength per diameter for the Independent Wire Rope Core (IWRC) for the 6×19 and 6×37 Improved Plow Steel (IPS).

Dia. (in.)
Weight per ft.Breaking Strength (tons) Stainless Steel (6×19)Breaking Strength (tons) Stainless Steel (6×37)Breaking Strength (tons) Galvanized IPSBreaking Strength (tons) Bright IPS
1/4″0.11 2.72.652.94

This comprehensive overview helps you understand the key aspects of wire rope strength, ensuring you select the right type for your requirements.

Types of Hitches

Let’s break down the different types of hitches you can use with wire rope slings. Think of hitches as how you can connect the sling to the load and the lifting device.

different kind of rope in an anchor

  • Choker Hitch – Think of it like giving your load a tight hug. One end of the sling hooks to the lifting hook, and the other wraps over to grip it tightly. Great for lifting snugly, but remember, the tighter it grips, the less it can lift.
  • Basket Hitch – This is like making a hammock for your load. Both sling ends go over the lifting hook, creating a basket shape. It’s stable and perfect for evenly spreading the weight of delicate or balanced loads.
  • Bridle Hitch – Ideal for heavy or awkward items. Multiple slings team up, each attaching to a different point on the load and meeting at the lifting hook. This setup evenly shares the weight, keeping everything steady.
  • Vertical Hitch – The simple, direct way to lift. One end of the sling attaches to the lifting device, the other to the load. It’s a no-fuss approach, but make sure your load can be lifted straight up.

Now you’ve got a quick guide to four common hitches. Each has a unique way of safely and efficiently lifting different loads. Next time you lift something, pick the right hitch for the job!

Troubleshooting Common Issues with Wire Rope Slings

Let’s tackle some common issues you might encounter with wire rope slings and how to fix them. It’s like playing detective – spotting the problem and knowing how to solve it.

Common IssueWhat It Looks LikeSolutionPreventive Measures
UntwistingThe sling starts to unravel or lose its twist.Rewind or re-lay the sling under professional guidance.Regularly inspect and ensure proper handling and storage. Avoid overloading.
KinkingSharp bends or twists that distort the rope’s shape.If severe, the sling may need to be replaced. A professional can sometimes straighten minor kinks.Avoid dragging the sling on the ground. Always coil properly for storage.
CorrosionRust or discoloration, especially in areas with high moisture or chemical exposure.Clean the affected area. If corrosion is severe, replace the sling.Store in a dry, clean area. Regularly clean and inspect slings, especially after exposure to harsh conditions.
Wear and TearVisible wear like broken wires or severe abrasion.Retire and replace the sling if wear is significant.Regularly inspect for wear. Use protective sleeves where necessary. Avoid dragging the sling.
OverloadingDeformation or elongation of the sling after use.Immediately cease use. Inspect and likely replace the sling.Always adhere to the sling’s load capacity. Use a load calculator if unsure.

Remember, keeping your wire rope slings in top shape is all about regular checks and smart handling. Spot the issue early, and you’ll save yourself a lot of trouble. Stay safe out there!

Frequently Asked Questions

  • Are Wire Rope Slings Suitable for Delicate Loads?
    • They can be with the right touch. Consider using slings with softer surfaces or protective sleeves for delicate loads to prevent damage. It’s all about matching the sling to the sensitivity of the load.
  • Can The Same Wire Rope Sling Be Used for Different Types of Lifts?
    • Sure, but it’s like using a multi-tool – good for many jobs, but not always perfect for every situation. The same sling can adapt to different lifts, but ensure it’s suitable for the weight, shape, and lifting method each time.
  • Is There a Difference in Performance Between a Single-Leg and Multi-Leg Sling?
    • Single-leg slings are great for straightforward, vertical lifts. Multi-leg slings, with their multiple points of contact, offer better load balance and control, especially for irregularly shaped or bulky items.
  • How Do I Choose The Right Diameter for a Wire Rope Sling?
    • Selecting the diameter is like choosing the right-sized wrench for a bolt. Consider the weight and nature of the load, the type of hitch you’ll use, and the sling’s angle during lifting. Consult with a lifting expert or refer to load capacity charts when in doubt.
  • Are There Specific Regulations I Should Know About Using Wire Rope Slings?
    • There are industry standards and regulations, often set by bodies like OSHA or ANSI. These cover everything from load limits to inspection requirements. Staying up-to-date with these regulations is key for safe and compliant operations.




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About Sam Orlovsky

AvatarCertifications: B.E.E.
Education: University Of Denver - Electric Engineering
Lives In: Denver Colorado

Electrical engineering is my passion, and I’ve been in the industry for over 20 years. This gives me a unique ability to give you expert home improvement and DIY recommendations. I’m not only an electrician, but I also like machinery and anything to do with carpentry. One of my career paths started as a general handyman, so I also have a lot of experience with home improvement I love to share.

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