Application of the Compressive Force Method to the Angle Control Method of Bolt Tightening

In this study, the new angle control method to reduce the scatter band of clamping forces has been developed. The present method simultaneously loads a bolt with torque and compressive force, and measures torque and angle. The friction coefficients, the snug point and the spring constants of the bolted joint can be accurately evaluated during tightening process. Thus, the scatter band of clamping force in the elastic region can be reduced within the error of 10% under oil free or lubricated conditions by the present method. The present method have high reliability and never loss tightening efficiency. It is possible to apply the present method to the plastic region tightening.