Fine tuning knife cutting bar for borer

The utility model discloses a trimming cutter bar applied to a borer, aimed at settling the problems that the existing boring and hole machining need the operator to regulate the dimension of extension of the boring cutter by sensation and experience which causes low efficiency and low yield. The trimming cutter bar comprises a boring bar mounted on an existing boring machine, a boring cutter (consisting of a cutter head and a cutter rod) mounted in the cutter hole and is fixed by a cutter-pressing screw, inside the cutter hole, a regulating screw rod which can be used to fine tune the extension dimension of the cutter can also be mounted. As regulation of the extension dimension of the cutter on the boring bar depends on the differential motion of different thread pitches at both ends of the regulating screw rod, and the dimension is changed by revolving the differential bolt, when the above cutter bar is adopted, the fine tuning extent can be calculated accurately in accordance with the rotation angle of th