Torque Wrench Extension / Crowfoot Correction
The wrench setting a crowfoot or in-line extension demands, which bolt-torque never gives: TW = TA x L / (L + E cos(angle)), the target torque scaled by the wrench lever L over the lengthened lever. A 3 in in-line crowfoot on an 18 in wrench targeting 100 ft-lb means dialing 85.7 - set it to 100 instead and you apply 116.7 ft-lb, a 17% over-torque that snaps small fasteners. Swing the crowfoot to 90 degrees and cos goes to zero, so no correction is needed - the field workaround. A shop aid; the calibrated wrench and the manufacturer's torque spec govern.
Formula and source
E_eff = adapter_length x cos(adapter_angle); TW = target x wrench_length / (wrench_length + E_eff); actual_if_uncorrected = target x (wrench_length + E_eff) / wrench_length; correction_pct = (TW - target) / target x 100.
Standard torque-adapter correction (Snap-on / FAA AC 43.13.1B torque-wrench extension relation) by name; first-principles lever statics.
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