Rock Drilling Bits and Their Classification
There are two types of drill bits for rock drilling tools: integral drill bits and movable drill bits. The integral drill bit is also called self-edging drill bit, the drill bit and the drill rod are inseparable; the movable drill bit can be separated from the drill rod, the disassembly is flexible and convenient, and it is widely used.
Bit types can be classified according to the distribution of chisel blades:
Commonly used one-word drill bits, cross drill bits, column-tooth drill bits, etc.
The common characteristics of these shapes of drill bits are: the thickness of the drill bit body is large, the drill hole is relatively round, it is not easy to jam, the force of the drill blade is in good condition, and the disadvantage is that it is difficult to manufacture and repair.
Slotted drill bits are easy to manufacture and sharpen, and are suitable for drilling medium-hard and above-medium-hard rocks. However, in rocks with well-developed joints and cracks and high toughness, the drill bit is easy to get stuck and the effect is poor. There are two types of slotted bits: hollow and solid. In brittle rocks, the drilling efficiency of hollow slotted bits is higher than that of solid slotted bits.
The cross drill bit is more complicated to manufacture and grind than the straight drill bit, and the consumption of cemented carbide sheets is also higher. It is suitable for heavy rock drills to drill hard rock, especially in rocks with developed joints and fissures, and it is not easy to get stuck.
The column-tooth bit has an angle of 105°and 75°between the hard alloy sheets. It can ensure the roundness of the drilled hole section, but it is difficult to manufacture. It is mainly used for drilling medium and deep holes with large diameters.
