Nine Important Rules to Follow When Using Shackles

Nine Important Rules to Follow When Using Shackles


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

Christie Lagowski

Christie Lagowski is a Communications Specialist for Columbus McKinnon Corporation.

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44 Replies to “Nine Important Rules to Follow When Using Shackles”

  1. Hello Siobhan,
    The pin/lug side of the shackle is heavier than the bow. When connected pin-to-pin, the lower shackle can easily roll, which will create a side-load. The lugs (where the pin goes through) have a larger outer diameter than the space between their interiors. When the shackle rolls, and is subsequently loaded, one of the lugs will be up against the interior space between the lugs of the other shackle. The rounded contour of the lug will act as a wedge, forcing the lugs of the top shackle apart.
    Thanks for reaching out to us,

  2. Hello, would you go into greater detail as to why pin-to-pin is a “never”. We see it may “shift the load from centerline,” but could you provide detail as to why that is so dangerous?

    It’s easier to encourage safe practices when we can provide detail on the physics. Thank you!

  3. Hello Mandu,

    The answer is no. Under ASME B30.26 which includes shackles, the use of any hardware not supplied by the original manufacturer would be considered a modification and therefore no longer meeting the standard.


  4. Hi Harry,
    Thanks for reaching out to us. We are fine with you including our content in a document for your clients.

    2) If online, then we would like you to include a link back to our blog.
    3) If printed, please include the following information: Columbus McKinnon Corporation,

    Thank you! It is always good to hear that our content is adding value to you and your clients.

  5. I own a production company and wondered if I could take this content and put this in a document to our clients? We will obviously reference CM

  6. very comfortable explain about shackle. i really appreciated of your expertation skilled

  7. Hi Scott,
    Are you possibly referring to the bend radius of the wire rope rather than the shackle capacity? To confirm, if the wire rope goes around too sharp a bend, it will have a reduced load capacity. Getting the desired bend radius may require using a shackle with higher capacity than the load alone requires.

    There is a lot of thought on what the bend radius compared to wire diameter should be. The required diameter is also different if the wire rope sling eye is made with a thimble. Different groups say different things. Synthetics also have the same issue. Sometimes it’s referred to as a d/d ratio.

    Here is a resource that may help:


  8. You state that shackle should be egual or one size
    larger than wire rope size #5. Not sure where nccco
    got this but in “NCCCO Rigger Reference Manual”
    on page 27 figure N-184-4 there an example of eye to
    eye straight pull vertical and at end fittings it says min.
    diameter of curvature at least double the diameter of the rope.
    If I’m reading that right half inch sling needs a 1″ shake? Seems
    like an awfully big shakle!

  9. 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.


  10. 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?

  11. 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.

  12. 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!

  13. 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.

  14. 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!

  15. 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.

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


  17. 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.

  18. 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.

  19. 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.

  20. 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.

  21. 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,

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

  23. 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.


  24. 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.

  25. 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.

  26. 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.

  27. 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.

  28. 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

  29. 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.

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