Nine Important Rules to Follow When Using Shackles


by  and  on December 10, 2015


Shackles are used every day in a variety of rigging and load securement applications. Before you use a shackle, there are nine important rules to keep in mind.

Rule 1:

When making a sling, attach multiple sling legs to the bow, not the pin. Attaching legs to the pin can damage and weaken the sling.

Rule 2:

When point loading shackle to shackle, connect bow to bow or bow to pin. Never connect pin to pin.

Rule 3:

Do not side load “D” shaped shackles such as chain shackles or long reach shackles. These shackles are designed and rated for in-line applied tension. Therefore, the center line of the load should coincide with the center line of the shackle. Anchor body style shackles (screw pin style, as pictured above, or bolt nut cotter anchor body style) can be side loaded. Always refer to reductions in rating charts when performing this type of rigging.

Rule 4:

When securing a load, the bow of the shackle should be put into the running side of a choke.

Rule 5:

When using a shackle with wire rope, the shackle must be equal to or larger than the wire rope diameter.

Rule 6:

If using a shackle with synthetic slings, ensure the shackle is big enough to avoid pinching or binding the sling.

Rule 7:

Shackles should not be subjected to high or low temperatures that could affect thermal treatment and the strength of the shackle.  -4 degrees F to 400 degrees F is the operating range for full working load limit.

Rule 8:

Always ensure shackle pins are properly engaged. Screw pin shackles need to have threads fully engaged on the shackle ear. (The pin should be flush with the outside of the shackle body or slightly past). The pin head should make contact with the shackle body. Bolt nut and cotter shackles need to have the bolt and nut properly secured with the cotter pin attached.

Rule 9:

Use bolt nut cotter anchor style shackles, if shackles will remain in place as a semi-permanent application or if they will be suspending a load. Screw pin shackles are used when the shackles are removed after the lift is complete. If a screw pin shackle is being used to suspend the load for any length of time, it is advisable that you mouse or tie off the pin to the body of the shackle with wire.
Want to learn more about safe shackle use? Here are some additional resources:

Shackle Markings, Materials and Appropriate Standards
New CM Shackle Markings and Pins Lead to Improved Operator Safety
Customer Concerns over Recommended Shackle Pin Length
Safety Webinar: Proper Use of Shackles 

Last updated on 12/21/15

{ 33 comments… read them below or add one }

Troy Raines Troy Raines March 14, 2017 at 9:44 am

Hi Al,
Cotter pins can be a variety of materials and finishes. Most often they are either stainless or plated. Different materials have different corrosion rates. Additionally the galvanizing on the shackle may even provide some corrosion resistance for the cotter pin through a process called cathodic protection.

The best indicator of how often an inspection should be done is history. In other words, start out inspecting pretty frequently and schedule future inspections based on how often your particular application affects the product in question.

To paraphrase ASME B30.26, a thorough periodic inspection must be done at least once a year. It may need to be more often depending on the frequency of use, the severity of conditions, nature of activities, and experience gained on the service life of shackles used in similar circumstances.


Al March 13, 2017 at 11:25 am

When using galvanized shackles for salt water (anchoring) applications, are the cotter pins generally galvanized too or not? If not, is it safe to assume that inspecting the cotter pins every few months should be sufficient to ensure their condition?

pooja February 15, 2017 at 7:26 am

Thanks for providing all rules with details

sunil February 14, 2017 at 6:21 am

Thanks for this useful information !

Peter Cooke Peter Cooke January 13, 2017 at 10:10 am

Good morning Debbie,
This is due to the D/d ratio (diameter of Rope “D” and diameter of shackle body “d”) in order to achieve full working load limit. Anything smaller can distort the wire rope without taking proper working load limit reductions.

Troy Raines Troy Raines January 13, 2017 at 9:59 am

Hi Wesley,
Thanks for your question. I have some additional insights I would like to share with you.

The ideal way to load a shackle is to center the load in the bow or saddle of the shackle and on the pin, with mating objects close to the same diameter as the shackle pin or bolt. This ideal condition applies the load over a rounded surface of sufficient diameter to prevent cutting the pin, and small enough diameter to allow the shackle to deform into a shape where the load is primarily in tensile if overloaded.

However, achieving this ideal condition in the field is not always possible. Therefore, in practice, it is recommended that the mating objects be as close to the pin or bolt diameter as possible and that the load be centered as near as possible in the bow or saddle of the clevis and on the center of the pin or bolt. Placing washers on the pin to center the load is acceptable.

Though some point loading is unavoidable and acceptable, severe point loading is to be avoided since a very small mating object (less than 1/4 the diameter of the clevis pin or bolt) will have a tendency to cause localized material failure on the body of the shackle or pin.

We appreciate you reaching out to us!

Debbie Schmaltz January 12, 2017 at 10:41 am

Good morning.
I was reviewing your article “Nine Important Rules to Follow When Using Shackles”
Can you explain why it must be equal to or larger than wire rope diameter?

Rule 5:
When using a shackle with wire rope, the shackle must be equal to or larger than the wire rope diameter.

Thank you very much. I look forward to your response.

Peter Cooke Peter Cooke January 11, 2017 at 8:41 pm

Hi Wesley,

Thank you for reaching out to us.
I would concur. Point loading is not ideal, but acceptable.


Wesley Munie January 6, 2017 at 6:03 pm

Good evening,

I was curious if you had any information on the down rating of a shackles max working load due to point loading? I recently ran into a surveyor who insisted the max working load of shackles should be down rated due to point loading of shackles during a lift. I was not able to find any information supporting what he had said other than an excerpt from a Crosby catalog stating point loading is not ideal but acceptable.

Thank You!

Peter Cooke Peter Cooke December 21, 2016 at 3:12 pm

Hi Sarah,
We don’t have a picture. There is no rule as to what size wire. I would use a wire that is easily bendable that can be wrapped around the body two to three times and go through the hole two to three times. A rigger should be checking the shackle frequently.

Sarah December 19, 2016 at 11:05 am

Do you have an example of a mousing on a screw pin shackle that you could share? Or a preferred size of wire?


Peter Cooke Peter Cooke November 4, 2016 at 12:10 pm

Hello Albert,
There is no rule as to what size synthetic sling can fit into a shackle.
What you have to be aware of is not to bunch up or layer the sling in the shackle.
The sling should lie flat across the shackle and be able to distribute the load across that shackle pin or bow.
Inspect the shackle for any defects that can cause harm to the sling. If you find a defect, replace the shackle.

Albert November 2, 2016 at 3:36 pm

Please can a 1″ nylon sling fit into a 3/8″ shackle when making a basket hitch?

Peter Cooke Peter Cooke October 17, 2016 at 6:37 pm

Hello Jennifer,
Yes. Keep in mind that if the shackles are not in-line (loading bearing point to bearing point) you must take proper reductions per charts supplied by the manufacturer and/or ASME B30.26.

Jennifer October 12, 2016 at 2:01 pm

Can you safely execute a lift “shackle to shackle”

Henry Brozyna Henry Brozyna September 19, 2016 at 6:33 pm

Hi Charles,
So sorry. I have checked with my colleagues on our training team and none of us have a picture of what you are describing.

Charles September 19, 2016 at 8:43 am

Hello I was wondering if anyone had a picture of an acceptable wire securement of a screw bolt to shackle body for suspending loads from a screw bolt style shackle assembly. Thank you.

Peter Cooke Peter Cooke July 8, 2016 at 9:42 am

Hi Ryan,
My apologies for our delay in response. I am confused about your application. The bow to pin is achievable with a wider bow dimension on the shackle. Can you please tell us more about your application?
Thanks for reaching out to us,

Ryan June 16, 2016 at 4:08 pm

What about pin/pin on wide body shackles? The wider bow dimension prohibits them from being installed bow/pin.

Peter Cooke Peter Cooke May 19, 2016 at 12:26 pm

Hi Steve,

A pin to pin connection can cause the shackle to shift from the centerline. It is safer to go with pin to bow or bow to bow.


Steve May 18, 2016 at 10:25 pm

What is or are the structural factors that make pin to pin rigging a “never”.

Peter Cooke Peter Cooke March 15, 2016 at 2:01 pm

Hi Joe,
Thanks for writing us. It is an acceptable practice for synthetic slings, but not for chain.

Joe March 14, 2016 at 9:34 pm

Comment/question- is it acceptable to shackle two slings together when lowering loads through the steel? I think a longer sling would be the best as the intention is to keep the hook above the structure to avoid any possibility of the hook getting caught on any part of the structure so I would think a shackle could cause the same hazard. So my question is it a bad practice or is it an unacceptable one? I took the EPRI course a couple years ago and believe I remember that being unacceptable but not for sure.

Gisela Clark Gisela Clark February 5, 2016 at 3:11 pm

Hi Steve,
Thanks for your comment. Great tip. A picture is worth a thousand words! We will work with our Training team to see what we can pull together.

Steve January 31, 2016 at 3:42 pm

Each items should have diagrams to show how to do it right.

Peter Cooke Peter Cooke December 18, 2015 at 10:06 am

Hello Chris,
Thanks for your comment. Being conservative is a great practice, however, there are many situations that will put shackles in a side load. Therefore, always refer to reductions in rating charts when performing this type of rigging. ASME B30.26 also includes these charts.

Peter Cooke Peter Cooke December 18, 2015 at 10:01 am

Hello Tansy,
It is the running side of the choke. “Bite” not bit. It is more of slang used by riggers. We will restate the text to read “the running side of the choke.” Thank you.

Tansy December 17, 2015 at 2:55 pm

RE: #4. I’ve never heard the terminology “bit of a choke.” Is the “bit” the straight/running side of the choke? In other words, pin always in the thimble of steel or loop of the spanset when choking.

Or do you mean bight? In which case, #4 would say the opposite of what I just suggested

Chris December 17, 2015 at 2:32 pm

I don’t think it is wise to suggest that any shackle can be used in side load. (As stated in rule 3)
It goes against “best practices” and can lead to confusion. Better to never side load and not worry which type of shackle you are using.
It’s one of those “just because you can doesn’t mean you should” situations.

moraka December 15, 2015 at 3:06 pm

thanx alots 4 let me knw coz i did semi skilled still looking for a job

Gisela Clark Gisela Clark December 14, 2015 at 8:40 am


Yes! Thanks so much for letting us know. We have since corrected it.
All the best,


Greg Peters December 13, 2015 at 8:43 pm

Is there a typo on #9?
Should it begin with Use bolt, NUT cotter.
Instead of bolt NOT cotter?

John December 11, 2015 at 11:51 am

Great advice thanks I will be sharing in my classes

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