Multifunctional microadjustment precision boring bar

The utility model relates to a boring bar; the lower groove of a fixed bar is provided with a mobile cutter sliding block which is screwed in the screw holes of the fixed bar and the sliding block by means of a regulating screw rod, and the pitches of the two screw holes are unequal, so the synchronization discrepancy type is formed; the regulating screw rod can be adjusted to make relative displacement between the sliding block and the fixed bar, and the cutter is arranged in the cutter supporting sleeve of the sliding block. The utility model has the advantages of simple structure, wide purpose, and high precision; as the boring bar is used, the single side can reach 0.005 millimeters, and the bilateral sides can reach 0.01 millimeters; if the boring bar is provided with a key groove milling cutter, key groove milling can be carried out; particularly a large key groove more than 45 millimeters, the boring bar can also be used for grinding technological holes, and the boring bar is suitable for grinding, milling, and boring machine.