In roadway drilling, enterprises usually choose appropriate equipment according to roadway size, rock compressive strength, rock compactness, and integrity. Advanced and high-power rock drills are widely used, which requires the higher performance of rock drilling tools, so the right rock drilling tools will provide a guarantee for efficient, high-quality drilling.

How to choose rock drilling tools for mine roadway excavation?

1. Thread

Most rock drills are connected with 38 mm threads, that is, T38 or R38. The choice of T or R threads is mainly based on the rock conditions and work requirements.

① R thread. It is a tighter connection, which reduces the loss of energy in the process of energy transfer and also reduces the heat generated by loosening. From another point of view, the wave thread is not easy to disassemble. If the equipment can provide a large enough propulsion and rotation force, T thread will be a better choice.

②T thread. It has a higher pitch and a larger contact surface, which is wear-resistant and easy to disassemble.

2. Shank adapter

Shank adapter has an important role in rock drilling tools, mainly transmitting torque, propulsion pressure, and impact pressure. It should be able to withstand not only the impact energy but also the rotational torque caused by friction against the rock while drilling. The selection of shank adapter is basically based on the model and specification of rock drill, and the length of shank adapter should be considered in conjunction with the propulsion beam and the length of drill rod. Since the shank adapter is closely connected to rock drill, the internal structure of the drill already determines the diameter of shank adapter, the size of the rotary spline, and the location of the drain hole. At the same time, it is important to use a highly reliable shank adapter to avoid damage to the internal structure of rock drill due to abnormal failure of shank adapter.

3. Coupling sleeve

Coupling sleeve is mainly to connect the shank adapter and drill rod and make the end faces of drill rod and shank adapter can be connected face to face to transfer energy effectively.

4. Drill rod

As the most important part of the whole rock drilling tools, drill rod is mainly used to transfer energy during the drilling. In underground roadway drilling, hexagonal drill rods are used in most cases. Compared with the round drill rod, hexagonal drill rods are made of more material, have higher fatigue strength, and are more rigid throughout. If the diameter of the end face of impact piston is closer to the diameter of the end face of shank adapter, the more effective energy transfer will be.

The selection of drill rod mainly considers 4 points.

①Thread for connecting shank adapter.

②Determining the length of drill rod by the length of advancing beam.

③Choose the correct diameter of drill rod so that the drill rod can rotate freely and have a reasonable annular gap to achieve the effective slagging effect.

④Consider the above factors to determine the thread of the end of rock drill bit.

 5. Rock drill bit

As the end point of contact with the rock, it is particularly important to choose rock drill bit to be able to use the effective energy to break the rock and reduce the reaction force. It is the main reason why there are more rock drill bits and models than other rock drilling tools.

The selection of rock drill bit is mainly based on different application conditions, such as rock conditions and drilling requirements, through which the appropriate carbide column diameter, shape, protrusion height, and edge tooth angle. Usually, the carbide button includes conical button, parabolic button, and ogive button, different button shapes have different rock drilling efficiency. Choosing a carbide button mainly considers the requirements of drilling speed, drilling accuracy, and service life of rock drill bit.