Get Hooked: All About Clevis Grab & Slip Hooks, Eye Hooks & More
We’re hooked on hooks at Hercules SLR!
There are many different hooks used for towing, pulling, securing, lifting and rigging, and each type of hook comes with different openings, latches, sizes and more. Hooks are often used to create sling assemblies (particularly with chain), and are also used in various transport applications.
It can be difficult to remember them and what they’re used for, so Hercules SLR wants to make it easy—We’ve made this comprehensive hook guide to secure your hook know-all.
This hook guide will cover topics like what is a below-the-hook lifting device, some of the most often-used hooks for securing and rigging, including non-overhead hooks, overhead lifting hooks, transportation hooks, what the different hook & chain ‘grades’ mean, plus tips for maintenance, inspection, ASME hook standards, and more.
Ready to get hooked on rigging? Read on!
What Exactly is a Below-the-Hook Lifting Device?
A below-the-hook lifting device is ‘any device used to connect a load to a hoist. The device may contain components such as slings, hooks, and rigging hardware…” A below-the-hook lifting device is a piece of equipment connected to a crane or other lifting device which grabs an item so it can be moved or secured to different place.
To that end, you might think that cranes and other lifting decides are known as “above-the-hook” lifting devices, however, they’re more often referred to as ‘overhead lifting devices’, and are rarely referred to as above-the-hook.
Clevis & Eye Hooks: What’s the Difference?
A clevis hook refers to a hook with a U-shaped attachment point or coupling with holes to thread a pin through and assemble your rigging—Many people like the removable pin to assemble and disassemble rigging quickly & easily. Clevis hooks are used for non-overhead applications.
You’ll likely hear the term ‘clevis’ used to describe other metal pieces of hardware with a clevis coupling. Hooks with clevis attachments can also be used for overhead lifts in many cases (Remember, they’ll be marked as Grade 80 or higher).
An eye hook (non-cradle grab & slip hook) is also used for non-overhead lifts, and is often used with tie-down equipment.
So, what’s the difference between eye hooks and clevis hooks? The attachment point/coupling. An eye hook has a rounded attachment point/coupling, unlike a clevis hook, which comes with a cotter pin to thread through the hole. Both can be used for overhead lifting, but are also often found alongside transportation securing and rigging set-ups.
Grade 70 chain and hooks are typically used to secure loads for transportation applications. Grade 80 is being used more often, however Grade 70 continues to be a popular choice for securement.
Securing, Lifting & Rigging
Rigging hardware is used to attach a load to the lifting point of a crane, and hooks are among some of the most popular rigging hardware.
- There can be different kinds of eye hooks—Hooks typically are eye or clevis hooks, which refers to the hook’s point of attachment.
- A hook with a clevis coupling or attachment point (see above).
- A hook with a swiveling coupling or attachment point.
EYE/ EYE HOIST HOOK
- Available in both carbon and alloy steel.
- A foundry hook is a type of grab hook.
- A grab hook does not usually feature a safety latch. It’s important to note that like clevis and grab hooks, other types of hooks can be grab hooks. For example, foundry hooks are a type of grab hook.
- A slip hook has a wider throat than a grab hook, and does feature a safety latch.*
- Sorting hooks have wide throat openings, which taper to a narrower basket. They have a slightly sharper tip than other hooks, and are used to quickly grab objects to lift. These are normally used in pairs, on steep angles.
* Safety latches are used to make sure the load stays connected under slack conditions. They’re not load-rated, and should never be placed under a Herculesload. Use hook latches unless unsafe to do so.
We’ll help you rig it right. What are we hooked on at Hercules SLR? We carry:
- EYE HOIST HOOKS
- SWIVEL HOOKS
- GRADE 80 WELD-ON BUCKET HOOKS
- G-100 EYE SELF-LOCKING HOOK
- G-100 CLEVIS SELF-LOCKING HOOK
- G-100 SWIVEL SELF-LOCKING HOOK WITH BRASS BUSHING
- G-100 SWIVEL SELF-LOCKING HOOK WITH BALL BEARING
- G-100 CLEVIS SLING HOOK
- G-100 EYE SLING HOOK
- G-100 CLEVIS GRAB HOOK
- G-100 ROUND SLING CONNECTOR
- GRADE 100 ROUND SLING HOOK
- G-100 GRAB HOOK
- G-100 SWIVEL GRIP SELF-LOCKING HOOK
- G-100 EYE FOUNDRY HOOK
- ALLOY EYE HOIST HOOKS
- ALLOY SWIVEL HOIST HOOK
- …And, we have replacement load pin kits for Grade-100 Clevis Hooks.
When Should a Hook be Removed from Service?
According to ASME B30.10 standards, hooks should be removed from service when they are:
- Missing/illegible hook manufacturer’s identification or secondary identification
- Missing and/or illegible rated load identification
- Excessive pitting or corrosion
- Cracks, damage and/or gouges
- Any wear that exceeds 10% (or as recommended by the manufacturer) of the original section dimension of the hook or its load pin
- Any visible deformations—This includes any bends, twists or other abnormalities from the plane of the unbent hook
- Any distortion that causes an increase in the throat opening of 5%, not to exceed 1/4″ (6mm), or as recommended by the manufacturer.
- Inability to lock or latch—If a hook has a safety latch, it must be able to close properly, or any self-locking hook that doesn’t lock.
- Damage, missing or malfunctioning hook attachment and securing means
Hooks should be inspected before, during and after use by the user. Rigging hooks should also be inspected periodically, or as recommended by the manufacturer.
Non-destructive testing is often used to determine if there are defects, nicks, gouges or any other deformations in metal gear or hardware, like hooks.
Grade 70, 80, 100—What do they all mean?
When we talk about ‘grade’ in relation to hooks, we actually refer to the grade of the chain that will be used with the hook. Grade refers to the tensile or breaking strength of chain.
Sound good? Let’s get into it:
NAME: Grade 70
PROPERTIES: Heat-treated carbon chain
APPLICATIONS: Use as a tie-down chain or transportation lashing.
DON’T DO THIS: Grade 70 chain is not meant for overhead lifting—Only use Grade 70 chain and hooks for tie-down and lashing applications.
FUN FACTS: You’ll likely hear Grade 70 chain called ‘trucker’s chain’. It usually has a gold-chromate coating that helps it resist corrosion, since their load is continuously exposed to the outdoor elements and things like salt from the highway also reduce their effectiveness. The gold colour also helps it remain visible for truckers.
NAME: Grade 80
PROPERTIES: Heat-treated steel chain
INDUSTRIES: Rigging, material handling & some transportation.
APPLICATIONS: Grade 80 chain is the minimum grade for overhead lifts, and is also often used in applications like recovery, safety & towing. Grade 80 chain is also often used with hooks in transport for flat-bed trucking to secure heavy loads.
DON’T DO THIS: Don’t use Grade 80 chain and hooks that are specifically marked for tie-down application in an overhead lifting capacity. (Hercules SLR’s Overhead Lifting Chain is meant for overhead lifting applications).
FUN FACTS: Will have 8 or 800 to denote that it is a Grade 100 chain or hook.
NAME: Grade 100
PROPERTIES: Alloy-steel chain
INDUSTRIES: Rigging & lifting—Mining, offshore, construction, material handling & maritime
APPLICATIONS: Sling component, popular for overhead lifts.
DON’T DO THIS: Use any hook to rig with—Use at least a Grade 100 hook with chain.
FUN FACTS: Will have 10 or 100 to denote that it is a Grade 100 chain or hook.
The More you Know
- These are some of the most commonly-found hooks in rigging—Some unconventional, or less-commonly found hooks include foundry, claw, bucket, ‘S’ hooks, alloy-swivel, plate & sorting hooks.
- Lifting hooks are constructed with a minimum 5:1 safety factor.
- Hooks should have a latch, or safety latch to connect the throat opening. This prevents load lines from disconnecting. Some overhead lifting devices may not have a safety latch or may have additional features that make using the latch impractical.
- NDT or non-destructive testing is a good way to check for deformities and defects in metal gear like hooks. We can find abnormalities on the inside and the outside of your metal gear.
- The load hook should be the weakest part of the lifting equipment.
- The hook tip should point out, away from the load, with no slack present so the hook won’t tip-load.
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Hercules SLR is part of Hercules Group of Companies, with locations and unique businesses coast-to-coast. We provide securing, lifting and rigging services for sectors in Canada and Internationally. Hercules SLR serves the energy, oil & gas, manufacturing, construction, aerospace, infrastructure, utilities, mining and marine industries.
We have the ability to provide any hoisting solution your business or project will need. Call us today for more information. 1-877-461-4876 or email email@example.com.