In this paper all experimental results of the torsion moment coefficients of high strength bolts with two kinds diameters, M27 and M24, and different plate combinations are presented.

This paper focuses on the effects of the distributed bolts and bolt-holes on the shell flange-end bending stress, and suggests a more practical calculation model on shell-end stress.

The reason of coupling bolt break is analyzed in this paper. Provide the experience for the design and installing coupling bolts of hydraulic turbine.