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What Makes Our American-Made Super Strong Shackle “Super”?

Breaking Down the CM Super Strong Shackle

Rigging | Safety and Training | By Troy Raines | Oct 14, 2019

SuperStrongShackle_thumb.jpgDesigned and forged in Chattanooga, Tennessee, CM Super Strong shackles are carbon-type shackles with strength ratings that are up to 50% stronger than comparable-sized carbon shackles. As a result, they are designed with a 6:1 safety design factor.

By using a special blended material, Columbus McKinnon is able to manufacture Super Strong shackles without requiring the quench and temper process. This gives our Super Strong shackles a higher working load limit (WLL) and greater design factor.

Our microalloy material is designed to be air-cooled from normal forging temperatures. This air-cooling process eliminates the potential for errors in hardness and strength or quench cracks in the heat-treating process.

The strength level of the microalloy forgings will be higher than the normal strength to hardness correlation allowing for greater ductility before failure.  The microalloy has the ability to distribute strain throughout the section more uniformly than conventional steels.  At the same hardness the microalloy will be stronger.

Below are Comparison Testing results of CM Super Strong Shackles versus Standard Carbon Shackles.  While all of the CM shackles performed above their ratings, the Super Strong shackle performance was superior.


Questions often arise about the difference between our Industrial/Government shackles and the Super Strong shackles. An Industrial/Government shackle is a Super Strong shackle de-rated to meet – not exceed – the Federal Specification RR-C-271. That means it has the same dimensions and performance characteristics as a Super Strong shackle but is stamped with specifications to meet government requirements.


1″ Super Strong shackle will be stamped 10 Ton WLL
1″ Industrial/Government shackle will be stamped 8 1/2 Ton WLL

But don’t just listen to us. Listen to an impartial opinion and see the results of a test performed by Arizona Wire Rope. This distributor tested on a Tonzilla 500,000 lb pull tester comparing the CM Super Strong shackle to our competitor’s shackle.

We have a full range of sizes and finishes in the Super Strong Shackle product offering. Find where to purchase CM rigging products and explore Columbus McKinnon's CM Rigging collection. 

Troy Raines

Troy Raines is a Global Chain and Rigging, Product Engineering Manager at Columbus McKinnon Corporation. He has 15 years of experience with CM on multiple ASME, WSTDA, ASTM, and ISO industry standards and technical committees. Troy believes that we are stronger/smarter as a team and enjoys strategic thinking that finds the best solution for all parties.

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