•Friction form on tightening screw pats, surface plate is controlled by axial tension stabilizer and also fluctuation of torque coefficient is controlled.

•As a result axial tension arises on tightening work is stabilized.

•Variation coefficient of torque coefficient is max 1/5 against machine oil.

•Relaxation characteristic is more than machine oil

•Fluctuation of torque coefficient on temperature change is small.