In drilling engineering, top hammer rock drill bits and DTH (Down-The-Hole) drill bits are popular tools, each with unique characteristics and applicable scenarios. For drilling workers, understanding the difference between the two and choosing appropriate tools is the key to improving work efficiency and ensuring project safety. This article aims to explain the differences between top hammer rock drill bits and DTH (Down-The-Hole) drill bits for drilling workers, helping readers better understand and apply these two tools.
The difference between rock drilling tools and DTH drilling tools
Before understanding the difference between rock drill bits and DTH drill bits, let’s first understand the difference between rock drilling tools and DTH drilling tools. Although in the field of rock drilling and blasting, both of them are rock drilling tools. It is called rock drilling tools used by rock drill and drilling tools for drilling large apertures used by DTH drilling rigs and roller cone drilling rigs. Rock drill bits belong to the former, and DTH drill bits belong to the latter.
As an additional note, the rock drilling tools mentioned above only refer to top hammer drilling tools. After all, there is not only one kind of rock drilling tool. According to the type of rock drilling machine used in rock drilling engineering, different from its supporting rock drilling tools, rock drilling tools include six types: top hammer drilling tools, DTH drilling tools, roller cone drilling tools, Reverse raise drilling tools, mechanical cutting drilling tools, and geological exploration drilling tools. The top hammer drilling tool is a rock drilling machine located at the top of the drilling tool. The piston of the rock drill directly hits the end of the rock drilling tools. The impact energy generated in the form of a stress wave passes through the rod to the drill bit to do work on the rock, including light rock drilling tools, drifting and tunneling tools, benching drilling tools, and open cutting drilling tools. The DTH drilling tool is different from the top hammer drilling tool. It is mainly a kind of medium and large-diameter rock drilling machine that uses compressed air as the power source and inserts the power part into the rock cavity to drill rock, including low-pressure DTH drilling tools and medium and high-pressure DTH drilling tools.
The difference between top hammer rock drill bit and down-the-hole drill bit
Different concepts
And then, let’s understand the meaning of rock drill bits and DTH drill bits.
Rock drill bit: It contains two parts: skirt body and carbide button. The drill bit skirt body and the drill rod are connected by threads and driven by the rock drill, and the drill bit carbide button drills and breaks the rock.
DTH drill bit: It connects the impactor with the spline of the drill bit to guide and transmit the rotation for the impact. The drill bit and the DTH hammer dive into the hole to break the rock.
From the above content, we can see that the rock drilling machines used by them are different.
The rock drill bit matches the rock drill used. A rock drill is a tool used to extract the stone. It drills blast holes in rock formations so that explosives can be put in to blast the rock, to complete the quarrying or other stonework.
DTH drill bits match the DTH hammers used. The DTH hammer is an integral part of the DTH drilling rig and belongs to the working device of the DTH drilling rig.
We can also distinguish them by the way they are classified.
Rock drill bit: according to the classification of the carbide button, it includes a conical button, parabolic button, and ogive button.
1. The conical button has high drilling efficiency and is suitable for medium-hard rock from f8 to f14, such as limestone, gravel, marble, pyrite, etc.
2. The parabolic button feeding speed is fast, which can not only ensure rock drilling efficiency but also have a better service life. It is very suitable for medium hard rock and moderately corrosive rock formations.
3. The ogive button has a fast button feed speed and excellent rock drilling efficiency. They are suitable for soft rock below f8, such as shale, clay rock, sandstone, and rock salt.
DTH drill bit: according to the structure, it includes a split drill bit and an integral drill bit.
1. Split drill: It has a head and a shank. If the drill bit is damaged, they can be replaced separately, to save steel, but the drill bit has low strength.
2. Integral drill bit: All in one. Compared with the split drill bit, it has high strength and can improve the energy transfer efficiency. The spline connection between the drill bit and the impactor is adopted to deliver large torque, uniform force, less wear, long life, and reliable work. However, it comes with high operating costs. According to the shape classification, rock drill bits and DTH drill bits both include the flat face, drop center, and semi-dome, but their scope of application is different.
| Bit face | Rock drill bit | DTH drill bit |
| flat face | Suitable for all rock conditions, especially for harsh or abrasive conditions such as granite, basalt, and hard limestone | It is suitable for drilling hard rock and corrosive rock at high wind pressure. |
| drop center | Drill straighter holes in less consolidated rock | Suitable for all rock strata, especially in the medium and hard rock good performance, drilling straightness is good, and slag discharge effect is good. |
| semi-dome | For soft rock, such as low-silica shale and limestone | Suitable for medium and low wind pressure drilling soft – medium hard rock, drilling speed is fast. |
Different working principles
Top-hammer rock drill bits mainly rely on the top hammering force for crushing. The crushing process primarily depends on impact and is supplemented by rotation. The DTH drill bit uses high-pressure gas to drive the drill bit to rotate and break the rock. The crushing process is mainly rotation and supplemented by impact. This difference in working principles results in variations in terms of crushing effect, drilling speed, and other factors.
Different applicable scenarios
Top hammer rock drill bits are suitable for drilling projects in medium-hard and below-hard rocks, especially in the drilling speed requirements are higher, the hole diameter is smaller occasions have advantages. The DTH drill bit is more suitable for drilling projects in hard and super-hard rock formations. Its robust crushing capacity and broad adaptability to various rock types enable it to excel in large-diameter and deep-hole drilling operations.
Different equipment configurations
Top hammer rock drill bits match the rock drill used. The equipment has a simple structure and is easy to operate. A rock drill is a tool utilized for extracting stone by drilling blast holes into rock formations, allowing explosives to be inserted for blasting purposes in quarrying or other stonework operations. DTH (Down-the-Hole) drill bits are paired with DTH drilling rigs. Although the equipment is more complex, it offers high drilling efficiency, making it well-suited for large-scale drilling projects.
How to choose the right rock drill bit?
When choosing between a top-hammer rock drill bit and a DTH (down-the-hole) drill bit, we should consider the project requirements, rock properties, hole size, drilling depth, and other factors. For projects with medium hard rock and below, high drilling speed requirements, and small hole diameters, a top hammer rock drill bit may be more suitable; for hard rock and super hard rock, large hole diameter, and deep hole drilling projects, DTH drill bits are more advantageous. In addition, we also need to consider the equipment configuration, maintenance costs, and other factors to choose the most cost-effective type of drill bit.
Conclusion
I believe that through the above content, you can know the difference between rock drill bits and DTH drill bits. Whether it is a rock drill bit or a DTH drill bit, to achieve the purpose of efficient and fast rock drilling, in addition to choosing high-quality products, it is necessary to choose the right rock drilling tools according to different drilling methods and rock types. If you don’t know how to choose, the supplier of the product is very important. Choosing professional and formal suppliers can not only provide enterprises with high-quality products but also provide professional advice on how to choose rock drilling tools.
