A circular saw mounting device which rotatably supports a saw blade in a grinding machine is disclosed. The mounting device comprises a base plate adapted for mounting in a grinding machine; a centering element comprising at least two engagement elements configured to be operated in a radial direction between a mounting position and a locking position. According to the invention the mounting device further comprises an actuator comprising a pin being configured to be operated in an axial direction and arranged to engage with pivot articulated couplings to each of the engagement elements to thereby transfer a radial displacement to the at least two engagement elements and to thereby operate the at least two engagement elements between the mounting position and the locking position.