“…High cutting speeds need to be got for a profitable boring process with good surface finish, which would increase the difficulties in boring of the non-circular hole. To create the wanted micro-displacement, the boring bar must be applied with direct or indirect radial actuation force, which can be got by such mechanisms as linear motor [1], [2], piezoelectric [3], [4], [5], hydraulic [6], voice-coil actuator [7], [8], etc. Due to the features of boring especially for subsize precision parts, it is difficult for above mentioned mechanisms to deliver ideal Manuscript Since the boring bar is in a high-speed rotation, the actuation force must satisfy the following conditions: 1) be exerted by contactless way, 2) rotate synchronously with the boring bar, 3) be great enough to put the boring bar to take a wanted radial micro-displacement about 20ȝor more [9], [10].…”