Wire-Rope Diameter for a Required WLL
The inverse of the wire-rope-strength estimate: the rope diameter for a required working load limit, d = sqrt(WLL x design factor / construction factor), then rounded up to the next standard size. A 5-ton WLL at 46 tons/in^2 and 5:1 needs 0.74 in -- pick 3/4 in (5.18 t). An ESTIMATE only; the manufacturer's certified rating governs, and unmarked rope must not be placed in service.
Formula and source
diameter_in = sqrt(wll_required_tons x design_factor / construction_factor), the MBS = factor x d^2 / WLL = MBS / design_factor rule-of-thumb solved for the diameter; round up to the next standard rope diameter.
Wire Rope Users Manual rule-of-thumb (by name), solved for the diameter; MBS = factor x d^2, no edition cycle.
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