Abstract: A self-locking head-replaceable carbide drill, comprising a cutter head disposed at the upper end of a cutter shank. A cylinder is disposed at the lower part of the cutter head, a vertical cylinder holding slot or cylinder handle holding hole is disposed at the upper end of the cutter bar, at least two cutter head notches are disposed on the drilling body of the cutter head, and each cutter head notch is formed by intersecting a first and a second cutter head contact face. At least two upward protrusions disposed on the wall of the upper end of the cutter bar and have the same number as the cutter head notches. When assembling the cutter head and the cutter shank, the cutter head ridge edges and the inner surfaces of the protrusions are in non-contact fit, interference fit and non-interference fit in sequence.

Abstract: The present invention discloses a self-locking head-replaceable hard alloy drill bit, comprising a cutter head and a cutter bar. The cutter head is disposed at the upper end of the cutter bar, a cylindrical handle is disposed at the lower part of the cutter head, a vertical cylindrical handle holding slot or round handle holding hole is disposed at the upper end of the cutter bar, at least two cutter head notches are disposed on the drilling body of the cutter head, and each cutter head notch is formed by intersecting a first cutter head contact face and a second cutter head contact face, which are vertical or vertically oblique. At least two protrusions which protrude upward are disposed on the wall of the upper end of the cutter bar and have the same number as the cutter head notches.