Diamond core drill belongs to one-piece drill bit, the whole drill bit has no moving parts. It has five parts: drill body, crown, hydraulic structure (including water hole or nozzle, flume also known as runner, chip removal slot), diameter preservation, cutting edge (tooth).
The crown of a diamond core drill is the working part of the bit in cutting rock. The surface (working face) of the bit is equipped with diamond cutting teeth and arranged with hydraulic structure. The side of the drill is a diameter-preserving part (with a diameter-preserving tooth mounted) which is connected with the bit body and is made of tungsten carbide matrix or steel material.
The drill body is made of steel, the upper part of which is connected by thread and drill string, and the lower part of which is connected with the crown matrix (the steel crown is integrated with the drill body).
The hydraulic structure of diamond core drill can be divided into two categories. A kind of natural diamond bit and TSP bit is used. The drilling fluid of this kind of bit flows out of the central water hole, disperses through the surface flume of the bit to cool, clean and lubricate the cutting teeth everywhere in the working face of the bit, and finally carries the cuttings into the annular space from the side flume and the debris discharge flume. The other is used for PDC bits. The drilling fluid of this kind of bits flows out of the water hole and is dispersed through various diversion elements to cool, clean and lubricate the cutting teeth in all parts of the working face of the bits. The position and number of water holes in PDC bits depend on the structure of the bits.
Diamond material's diameter-keeping part plays the role of centralizing the bit and ensuring that the diameter of the well does not shrink during drilling. Diamond is mounted on the side of the bit to achieve the purpose of diameter-keeping.