Estimate the tightening torque required to achieve a desired clamp load in a bolt. Critical for structural assembly and preventing fastener failure.
K is the nut factor or friction coefficient. 0.2 is standard for dry steel. Lubricated bolts have a lower K (0.15), meaning less torque is needed for the same tension.
Under-torquing leads to loose bolts. Over-torquing can strip threads or snap the bolt.
K=0.2 for dry steel.