Five-blade base PDC bit with 12.25'' outside diameter

The utility model provides a five-blade base PDC bit with 12.25'' outside diameter, which comprises a bit body, blades, nozzles, main cutting teeth, and gauge protectors, wherein the outside diameter of the PDC bit is 12.25''; the bit body has long blades and short blades; each long blade has nine main cutting teeth; each short blade has six main cutting teeth; the nozzles are arranged at the front ends of the long blades and the short blades respectively; the blades adopt 2.5'' standard gauge protectors which are distributed around the center of the crown part of the bit body, and the angles of distribution are 0 degree, 88 degrees, 148 degrees, 218 degrees and 278 degrees respectively; the diameters of the main cutting teeth are 19 mm; the main cutting teeth are arranged from near to far from the center of the bit body; the backward inclination angles of the teeth are gradually increased from 15 degrees to 22.6 degrees with an increase rate of 0.2 degrees; and the distribution numbers of the main cutting te