A drill bit working on solid material by circular cutting. By sparing the material cores, machining by trepanning drill can save more materials and reduce powers consumption. When it comes to test performance on sampling from material center, Trepanning Drill which in general works on the hole with diameter more than 60mm, seems to be one of irreplaceable cutting tools. It comes with cutting edges of drill bits in different shapes, designed to separate narrow chippings and with a bench on each cutter tooth to crush chippings, thus to assure a smooth chipping discharging and cutting load reduction. For nesting on blind hole with large diameter, special cutting device is required to separate the core material and the body.