Hole opener

The utility model discloses a tapper which comprises a rotating shaft capable of being connected with a power mechanism, a base arranged at the end of the rotating shaft, a main cutter body connected to the lower surface of the base, a positioning tip located in the center of the main cutter body and a cutting blade connected to the periphery of the base. The end of the main cutter body and the cutting blade are located on the same circumference, a notch part is formed between every two adjacent fixing blocks, a spiral chip guide groove is formed in the outer wall of the rotating shaft, and the tail end of the spiral chip guide groove corresponds to the notch part. The spiral chip guide groove is formed in the outer wall of the rotating shaft, chips generated during tapping firstly enter the notch part and then are discharged through the spiral chip guide groove, so that the chips can be continuously and smoothly discharged, the chip removal efficiency is high, the operation is labor-saving, the influence on