Customer Concerns over Recommended Shackle Pin Length

Customer Concerns over Recommended Shackle Pin Length

shackle pin length

Bill asks the following question about shackles and shackle pin length:

“I have a concerned employee because we have some screw pin shackles with pins that do not protrude past the clevis when fully engaged. I have looked in several rigging books and cannot find any information on the threaded pin. We have other shackles from another manufacturer, and those pins extend approx 1/16″ past the end of the clevis. I know this sounds trivial, but we need to address every safety concern raised by our crew members. I would appreciate any information you could provide on shackle pin length.”

shackle pin length Peter answers:

There have been many misconceptions on how a screw pin should be applied on a shackle.  Many riggers will tell you to get the pin snug then back off a 1/2 turn. This is incorrect.  The 2010 revision of ASME B30.26 Rigging Hardware, section 26-1.9.4 Rigging Practices states “The screw pin threads shall be fully engaged and tight, and the shoulder should be in contact with the shackle body.

 
So, to answer your question: The threads do not need to extend beyond the shackle body.
It is good practice to obtain the latest copy of the ASME B30.26 standard for more information.

Peter Cooke
Peter Cooke is a Training Manager specializing in Rigging & Load Securement for Columbus McKinnon Corporation.
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6 Replies to “Customer Concerns over Recommended Shackle Pin Length”

  1. Hello Kevin,
    If the screw pin threads easily in and the pin is fully engaged on the threads, the shackle will be acceptable. Due to manufacturers’ tolerances you may see one or two threads exposed on the shackle. If the pin threads are hard or difficult to tighten, then this is a good indication of body distortion.
    Peter

  2. The answer here lies in the threads showing INSIDE or between the ears. If 2 or more threads are showing inside, then the ears have spread and the shackle should not be used. The shoulder on the shackle pin will prevent the pin from fully penetrating the ear if the ear is damaged or the pin is not matched to the shackle body (mixed manufacturers caused by end users)

  3. Tim, thanks for your comment. There are manufacturing tolerances to consider. These are forgings not precision pieces. However, the pin and shackle should share 100% thread engagement. A flush or slightly protruding pin provides some assurance of full thread engagement. Also the pin would not thread easily if the shackle was stretched enough to compromise its integrity.

  4. I, like Bill, have been asked the question several times but I don’t believe your answer above speciafically addresses my concern. The concern is some rigging instruction groups are teaching that if the pins are not at least flush with (may extend past) the clevis end then that is an indication the shackle has spread and the shackle needs to be discarded. Is this true?

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