A. The major difference between these particular rope constructions is their rotational behaviour. In general it is possible to quote a 19×7 as “low-rotation” rope, where a 35×7 is usually “non-rotating”. These properties may influence the decision whether or not using a swivel. As a rough guidance the 19×7 should usually not be used with a swivel, where a 35×7 can be used with one. Please note that the use of a swivel may be subject to the recommendations of the rope manufacturer and/or approval of a competent person. More specific information can be found in ISO 21669 – “Steel wire ropes — Determination of rotational properties”. Especially “Annex A” of this particular standard gives a guidance on the use of swivels.
-Robert Traxl, wire rope R&D manager, Teufelberger Seil
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