<p>A wire electrode discharge grinding using a controllable slit (CS-WEDG) method is proposed for fabricating tapered micro shafts. The cone angle constraint formula of tapered micro shafts is obtained by analyzing the geometric model of CS-WEDG. This method can fabricate micro shafts with negative and positive taper by combining the feed path and wire electrode slit with an included angle, and it is not sensitive to the motion accuracy of the machine tool. The long feed distance in the <i>x</i>-axis and symmetrically arranged wire electrodes can disperse the wear of wire electrodes, which is conducive to improving the accuracy of tapered micro shafts. Effects of servo feed, asymmetric included angles of wire electrodes and wire electrode wear on the tapered micro shaft accuracy were analyzed through experiments. Servo feed can avoid the occurrence of a short circuit state, which is beneficial to improving contour accuracy. If the included angles of wire electrodes are asymmetrical, the wire electrode with a larger included angle plays a significant role in fabricating tapered micro shafts. Wire electrode wear will increase tapered micro shafts’ cone angle and contour errors. In the last step of finishing, the measure of replacing a new wire electrode and using a smaller cutting depth was used to fabricate tapered micro shafts with more minor errors of cone angle and contour. Finally, micro shafts with negative and positive taper that have cone angles of 1.5 ± 0.0313° and contour errors of approximately ± 1&#xa0;μm were repeatedly fabricated, which confirmed the feasibility and capability of the CS-WEDG.</p>