Torque tightening is a simple and quick method of tightening bolts, but the tension resulting from torque tightening depends on the coefficient of friction involved in tightening.
Friction is a difficult phenomenon to evaluate and quantify, so the accuracy of theclamping force in tension corresponding to the applied torque is relatively approximate unless tedious experimental designs are performed on identical conditions.
Torque and Angle tightening is an industrial tightening technique that reduces the uncertainty associated with the coefficient of friction by acting on the elongation of the bolt during tightening to directly control the applied tension.
Knowing the thread pitch, it is easy to calculate the angle the nut or screw must turn to give the desired tension and have better tightening control.
