Shackle Markings, Materials and Appropriate Standards

Rigging | By Columbus McKinnon Training | May 25, 2010

S. H. from Georgia writes:

I am unfamiliar with the standards governing shackles and have a question regarding the stamped WLL on your shackles. Our company is using shackles with different ratings on them.  For example, we use a ½” shackle stamped a 2T WLL and a ½” shackle stamped with a 3T WLL.  I understand that there was a change in the standard several years ago and wonder if you could recommend which load rating is the correct one and what should be done with the shackles with incorrect stamping.  Also, neither shackle is stamped or marked as High Strength “HS” as required by the standard RR-C-271D and Amendment 1.  Any information that you can provide would be appreciated.

Columbus McKinnon's Training team answers this question on shackle markings:

Both of the WLL stamps on your two types of shackles may be correct.  Shackles fall under ASME B30.26 rigging hardware.  Shackle working load limits differ based on materials used to construct the shackle.  The industry has three types of materials for shackles: CarbonSuper Carbon and Alloy.  This means that you can have three shackles of all the same size (diameter) and have three very different working load limits.  ASME B30.26 requires the working load limit be stamped on all shackles.  A rigger must look for the WLL stamped on the shackle.

This is why you must never base your working load limit by diameter. If the WLL is no longer legible, the shackle should be discarded.

The classification of a shackle as “High Strength” is based upon the classification of the shackle pin as HS. The HS stamp will be on the pin or bolt, not on the shackle.  All CMCO shackles – carbon, super carbon or alloy – have HS pins. So, you do not need to worry about mixing up pins between carbon, super carbon and alloy when using CMCO products.


See also Shackle Marking Reference File

Columbus McKinnon Training

Articles authored by "Columbus McKinnon Training" were written by industry professionals with decades of unique and in-depth experience in the material handling industry who are no longer employed by Columbus McKinnon.

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