Bolt Torque Calculations using Dennis Moss 4th Edition

A: A points to Moss’ empirical K-factor approach tied to lubrication state. B imports PCC-1 guidance but drops the friction assumption Moss is explicit about. C looks tempting but GA notes aren’t a design basis and miss preload intent. D is a different control method altogether and doesn’t answer a torque selection problem.

A: A drops the friction term entirely. B follows Moss’ back-of-envelope: 0.25×70,000 N×0.025 m lands in that band. C exaggerates friction without checking the multiplication. D confuses preload magnitude with torque scaling and overshoots by a factor of four.

A: A catches the N·m vs ft·lbf conversion that Moss repeatedly warns about. B assumes material grading fixes physics. C misunderstands lubrication; it reduces scatter, not unit errors. D relies on undocumented margin and ignores yield risk.

A: A follows Moss’ friction breakdown: lower friction at threads and bearing face raises tension. B mixes up damping with friction. C ignores the whole reason Moss decomposes torque. D contradicts itself; nut factor exists to link torque and preload.