SWT/K series 4 to 6 high-strength bolts are applied by a SWT/K series lock nut. It is locked by the axial deformation of its thread. It is suitable for severe working environment where nuts may easily been loosen and high torque is required. Run out can be adjusted by adjusting the tightening force of the axial screw. Material: 42CrMo,45#, 40Cr Hardness: HRC28°—32° Thread Precision: ISO4H Run Out: 0.007mm