Contributed by Bob Kozickie, Technical Sales Support Manager
Edited by Christy Kutchma, Product & Marketing Associate
There are three styles of grab hooks manufactured for overhead lifting: Non-Cradle, Cradle, and Chain Shortening Grab Hooks. Each are designed to shorten, choke, or basket alloy chain slings in a variety of lifting applications. When used correctly though, all three styles perform their functions with safety and reliability.
Non-Cradle Grab Hook
The non-cradle grab hooks’ existence has endured the test of time. It’s been a reliable hook that riggers have utilized since alloy chain slings first came into existence. The non-cradle grab hooks’ use in lifting applications has seen gradual reduction over the years due to safety concerns. The non-cradle grab hook requires that the rigger take a 20% reduction in sling capacity when used in any overhead lifting application. The chain sling itself is tested and certified at twice the working load limit under controlled ASTM conditions; however, the rigger is responsible to reduce the capacity when he utilizes the non-cradle grab hook. This requires that the rigger not only has to be aware of the hardware on his chain sling, he also has to take the extra step to calculate the maximum load he can lift with that chain sling when the non-cradle grab hooks are used. The 20% reduction may require that a larger diameter or higher chain grade chain has to be used to safely lift the load. It’s easier and much safer to equip the sling with one of the two other grab hooks so the margin for error is greatly reduced.
There is a reasonable explanation as to why the 20% reduction is required to be taken. Throughout the years, it was discovered that the alloy chain being used in conjunction with the non-cradle grab hook experienced a number of failures. The failures occurred in such a fashion that the chain appeared to have been cut rather than experience an elongation shear break due to overloading. The hook even received the nickname “Cutter Hook” by some riggers who had to use them on a regular basis. The main reason for this reduction is that the surface area at the bowl where the chain is in contact with the hook is narrow. Depending on the amount of grinding that is done at the forger to “clean up” the hook, the edges on which the chain rests can b