Convert Pound-inches to Newton-meters

Torque is the rotational analogue of force: a force applied at a distance from an axis. The SI unit is the newton-metre (N·m), and the US customary unit is the pound-foot (lbf·ft), with 1 lbf·ft equal to exactly 1.3558179483 N·m. Despite the same numerical factor, pound-foot (torque) and foot-pound (energy) describe distinct physical quantities — torque is a vector, energy a scalar. Automotive specifications quote engine torque in N·m or lbf·ft; most wheel lug nuts require 100 to 140 N·m (74 to 103 lbf·ft). Lower-torque work on bicycles, electronics and small fasteners uses pound-inches or newton-centimetres, where 1 lbf·ft equals 12 lbf·in. The kilogram-force metre (kgf·m), once common in European engineering, equals 9.80665 N·m thanks to standard gravity. The cgs dyne-centimetre persists in physics problems and older literature. Accurate torque matters because over-tightening fasteners induces thread yield while under-tightening risks joint separation, so fastener manufacturers publish torque ranges traceable to ISO 16047.