SECURING MECHANISM

A securing mechanism, mounted at an end of a workpiece shaft (2), and consisting of a brake wheel (7), brake pad support frames, brake pads, and a pneumatic cylinder construction. The brake wheel (7) is sleeved on a terminal end portion of the workpiece shaft (2), and the brake pad support frames are provided respectively on two sides of the brake wheel and have a lower portion supported by a workpiece container (1). The brake pad support frames have lower ends movably connected to the workpiece container (1), inner sides mounted with the brake pads, and upper ends connected with the pneumatic cylinder tightly holding the two brake pad support frames. By employing the pneumatic cylinder to tightly hold the brake pad support frames, the present invention enables the brake pads to tightly secure the brake wheel (7) sleeved on the workpiece shaft (2), thus preventing a cutting force during a milling operation of a milling cutter on an oil groove of a piston ring from causing rotation of the piston ring, and acco