Rigging | By Columbus McKinnon Training | Feb 08, 2011
National Association of Chain Manufacturers (NACM), representing domestic manufacturers of welded and weldless chain since 1933, has conducted D/d testing on alloy chain. D/d is the ratio between the curvature taken by the sling D, and the diameter of the component chain d. NACM alloy chain manufacturers supplied Grade 100: 9/32”, 3/8” and ½” and Grade 80: 3/8” for testing. Until this point, no published information was available for chain regarding D/d. NACM wanted to publish information to make recommendations on the minimum pin diameter for proof testing basket chain slings based on link deformation and rating/ derating of baskets and endless slings vs D/d ratio.
NACM testing results are shared below.
The chart below shows reductions in working load limit of an endless alloy sling based on D/d ratio. Consult the manufacturer for any D/d below 2.
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