A Down-the-Hole (DTH) drill bit is a rock drilling tool that connects to the hammer via a splined interface. This connection not only guides the impact force but also ensures efficient transmission of rotational motion.
The drill bit and hammer dive into the hole and use the force of impact and rotation to break the rock. DTH drill bits are used in large-scale open-pit and underground mining, anchoring projects, quarrying, construction drilling, and basic engineering projects.
Our DTH drill bits are available in three face designs—flat, convex, and concave—to suit the most common drilling conditions.
| Face Design | Applicable Rock Formation |
| Flat | Traditionally, the flat-face design is used in general-purpose drilling operations. It is particularly suitable for highly fractured ground, hard formations, and soft formations prone to damage from excessive drilling. This design performs exceptionally well in high-air pressure environments when drilling extremely hard and highly abrasive rock formations. |
| Convex | The convex face design is ideal for fast drilling in soft to medium-hard rock formations under medium to low air pressure conditions and is widely applied in various drilling operations. The unique convex design is particularly effective in hard and abrasive rocks, providing an excellent balance of high penetration rates and long service life. |
| Concave | The concave face bit is suitable for all rock types, excelling particularly in medium-hard rock drilling with outstanding hole straightness and efficient cuttings removal. As a versatile bit design, it adapts well to both hard and soft formations. Its conical face structure enhances stability during drilling, ensuring superior hole alignment and reduced vibration. Additionally, the strategic placement of tungsten carbide inserts maximizes penetration efficiency across various geological conditions. |
| Nominal diameter (mm) | Number of vent holes | Gauge Button | Front Gauge | Connection with Drill Pipe | Weight (kg) | Specifications |
| φ70 | 1 | 4×φ12 | 3xφ12 | φ37-4 | 1.5 | KQZ-70P |
| φ75 | 3 | 5×φ12 | 3xφ12 | φ43-6 | 2.4 | KQZ-75P |
| φ76 | 2 | 5×φ12 | 3xφ12 | φ44-4 | 2.5 | KQZ-76P |
| φ80 | 3 | 6×φ12 | 3xφ12 | φ50-6 | 3.0 | KQZ-80P |
| φ90 | 3 | 6×φ14 | 4xφ12 | φ50-6 | 3.6 | KQZ-90P |
| φ90 | 3 | 6×φ14 | 4xφ12 | φ54-6 | 3.8 | KQZ-90P1 |
| φ90 | 2 | 6×φ14(Ballistic） | 3xφ12(Ballistic) 1xφ12(Hemispherical) |
φ54-6 | 3.6 | KQZ-90P2 |
| φ90 | 2 | 6×φ14(Ballistic） | 4xφ12(Ballistic) | φ54-6 | 3.8 | KQZ-90P3 |
| φ90 | 3 | 6×φ14(Conical） | 4xφ12(Conical) | φ54-6 | 3.8 | KQZ-90P4 |
| φ90 | 2 | 5×φ14(Ballistic） | 4xφ12(Ballistic) | φ54-6 | 3.6 | KQZ-90P5 |
| φ100 | 3 | 6×φ14 | 4xφ12 | φ54-6 | 4.0 | KQZ-100T |
| φ105 | 3 | 8×φ14 | 2xφ12 | φ54-6 | 4.2 | KQZ-105T |
| φ110 | 3 | 8×φ14 | 2xφ12 | φ54-6 | 4.5 | KQZ-110T |
| φ120 | 3 | 8×φ14 | 3xφ12 | φ54-6 | 5.0 | KQZ-120T |
| φ130 | 3 | 8×φ14 | 3xφ12 | φ54-6 | 6.8 | KQZ-130T |
| φ110 | 3 | 6×φ14 | 5xφ12 | φ65-6 | 6.1 | KQZ-110P |
| φ115 | 3 | 6×φ14 | 5xφ12 | φ65-6 | 6.3 | KQZ-115P |
| φ120 | 3 | 6×φ14 | 6xφ12 | φ65-6 | 7.0 | KQZ-120P |
| φ125 | 3 | 6×φ14 | 7xφ12 | φ65-6 | 7.1 | KQZ-125P |
| φ130 | 3 | 6×φ14 | 7xφ12 | φ65-6 | 7.3 | KQZ-130P |
| φ135 | 3 | 6×φ14 | 7xφ12 | φ65-6 | 8.0 | KQZ-135P |
| φ140 | 3 | 6×φ14 | 8xφ12 | φ65-6 | 8.2 | KQZ-140P |
| φ150 | 3 | 6×φ14 | 9xφ12 | φ65-6 | 9.0 | KQZ-150P |
| φ155 | 3 | 14×φ16 | 4xφ14 | φ90-6 | 16.3 | KQZ-155P |
| φ165 | 3 | 14×φ16 | 5xφ14 | φ90-6 | 17.3 | KQZ-165P |
| φ180 | 3 | 15×φ16 | 8xφ14 | φ90-6 | 19.6 | KQZ-180P |
| φ200 | 3 | 18×φ16 | 3xφ14 | φ90-6 | 23.0 | KQZ-200P |
| φ175 | 3 | 15×φ16 | 8xφ14 | φ98-6 | 22.8 | KQZ-175P |
| φ185 | 3 | 15×φ16 | 8xφ14 | φ98-6 | 23.2 | KQZ-185P |
| φ190 | 3 | 9×φ16 | 13xφ14 | φ98-6 | 23.5 | KQZ-190P |
| φ195 | 3 | 9×φ16 | 13xφ14 | φ98-6 | 24.0 | KQZ-195P |
| φ200 | 3 | 18×φ16 | 5xφ14 | φ98-6 | 25.8 | KQZ-200P |
| φ205 | 3 | 18×φ16 | 6xφ14 | φ98-6 | 26.1 | KQZ-205P |
| φ210 | 3 | 9×φ16 | 13xφ14 | φ98-6 | 26.5 | KQZ-210P |
| φ220 | 3 | 14×φ16 | 12xφ14 | φ98-6 | 28.5 | KQZ-220P |
| φ220 | 3 | 15×φ16 | 11xφ14 | φ98-6 | 28.5 | KQZ-220P1 |
| φ230 | 3 | 15×φ16 | 12xφ14 | φ98-6 | 32.0 | KQZ-230P |
| φ240 | 3 | 15×φ16 | 11xφ14 | φ98-6 | 36.0 | KQZ-240P |
| φ250 | 3 | 15×φ16 | 13xφ14 | φ98-6 | 45.0 | KQZ-250P |
| Nominal diameter (mm) | Number of vent holes | Side teeth | Middle teeth | Connection with Drill Pipe | Weight (kg) | Specifications |
| φ90 | 2 | 6×φ13 | 6xφ12 | φ53-8 | 4.6 | KQZG-90P |
| φ100 | 3 | 6×φ14 | 4xφ12 | φ54-6 | 4.0 | KQZG-100P |
| φ105 | 2 | 8×φ14 | 7xφ13 | φ64-8 | 7.7 | KQZG-105P |
| φ115 | 2 | 7×φ14 | 7xφ13 | φ64-8 | 8.0 | KQZG-115P1 |
| φ130 | 2 | 8×φ14 | 8xφ13 | φ64-8 | 10.5 | KQZG-130P |
| φ115 | 2 | 7×φ14 | 6xφ12 | φ65-6 | 6.4 | KQZG-115P |
| φ120 | 2 | 7×φ14 | 6xφ12 | φ65-6 | 7.0 | KQZG-120P |
| φ130 | 2 | 7×φ14 | 8xφ12 | φ65-6 | 8.0 | KQZG-130P1 |
| φ140 | 2 | 7×φ14 | 10xφ12 | φ65-6 | 8.2 | KQZG-140P |
| φ150 | 2 | 7×φ14 | 8xφ12 | φ65-6 | 9.0 | KQZG-150P |
| φ130 | 2 | 7×φ16 | 7xφ14 | φ84-8 | 17.0 | KQZG-130P2 |
| φ140 | 2 | 7×φ16 | 7xφ14 | φ84-8 | 18.0 | KQZG-140P1 |
| φ152 | 2 | 8×φ16 | 8xφ14 | φ84-8 | 19.0 | KQZG-152P |
| φ152 | 2 | 8×φ16 | 11xφ14 | φ99.5-8 | 25.0 | KQZG-152P1 |
| φ165 | 2 | 8×φ16 | 11xφ16 | φ99.5-8 | 26.5 | KQZG-165P |
| φ178 | 3 | 12×φ16 | 6xφ14 | φ99.5-8 | 28.6 | KQZG-178P |
| φ194 | 3 | 9×φ16 | 12xφ16 | φ99.5-8 | 30.0 | KQZG-194P |
| φ203 | 3 | 9×φ16 | 13xφ16 | φ99.5-8 | 32.0 | KQZG-203P |
| φ216 | 3 | 9×φ16 | 13xφ16 | φ99.5-8 | 35.0 | KQZG-216P |
| φ230 | 3 | 12×φ16 | 16xφ16 | φ99.5-8 | 37.0 | KQZG-230P |
| φ254 | 3 | 12×φ16 | 17xφ16 | φ99.5-8 | 43.0 | KQZG-254P |
| φ305 | 3 | 15×φ16 | 27xφ16 | φ99.5-8 | 57.0 | KQZG-305P |
| φ203 | 2 | 8×φ18 | 10xφ16 | φ128-8 | 48.0 | KQZG-203P1 |
| φ216 | 3 | 16×φ18 | 7xφ16 | φ128-8 | 50.0 | KQZG-216P1 |
| φ230 | 3 | 16×φ18 | 7xφ16 | φ128-8 | 53.0 | KQZG-230P1 |
| φ254 | 3 | 16×φ18 | 9xφ16 | φ128-8 | 58.0 | KQZG-254P1 |
| φ310 | 3 | 21×φ18 | 14xφ16 | φ128-8 | 71.0 | KQZG-310P |
| φ350 | 4 | 32×φ18 | 23xφ16 | φ128-8 | 80.0 | KQZG-350P |
| φ302 | 3 | 15×φ19 | 23xφ19 | φ210-12 | 176.0 | KQZG-302P |
| φ311 | 3 | 15×φ19 | 24xφ19 | φ210-12 | 177.0 | KQZG-311P |
| φ330 | 3 | 15×φ19 | 31xφ19 | φ210-12 | 186.0 | KQZG-330P |
| φ357 | 3 | 15×φ19 | 34xφ19 | φ210-12 | 196.0 | KQZG-357P |
| φ381 | 3 | 15×φ19 | 40xφ19 | φ210-12 | 205.0 | KQZG-381P |
| φ444 | 3 | 18×φ19 | 44xφ19 | φ210-12 | 230.0 | KQZG-444P |
| φ483 | 3 | 18×φ19 | 50xφ19 | φ210-12 | 285.0 | KQZG-483P |
| φ508 | 3 | 24×φ19 | 74xφ19 | φ210-12 | 311.0 | KQZG-508P |
| φ110 | 2 | 8×φ14 | 7xφ13 | φ67-12 | 8.0 | KQZG-115P2 |
| φ130 | 2 | 8×φ14 | 8xφ13 | φ67-12 | 12.0 | KQZG-130P2 |
| φ130 | 2 | 7×φ16 | 7xφ14 | φ83-12 | 15.0 | KQZG-130P3 |
| φ140 | 2 | 7×φ16 | 7xφ14 | φ83-12 | 15.6 | KQZG-140P2 |
| φ150 | 2 | 8×φ16 | 8xφ14 | φ83-12 | 19.0 | KQZG-150P2 |
| φ165 | 2 | 8×φ16 | 9xφ16 | φ104.4-12 | 25.0 | KQZG-165P1 |
| φ178 | 2 | 8×φ16 | 10xφ16 | φ104.4-12 | 27.0 | KQZG-178P1 |
| φ203 | 2 | 8×φ16 | 13xφ16 | φ104.4-12 | 40.0 | KQZG-203P2 |
| φ216 | 3 | 9×φ16 | 14xφ16 | φ104.4-12 | 45.0 | KQZG-216P2 |
| φ203 | 2 | 9×φ18 | 9xφ16 | φ128-12 | 48.0 | KQZG-203P3 |
| φ216 | 2 | 10×φ18 | 12xφ16 | φ128-12 | 50.0 | KQZG-216P3 |
| φ254 | 3 | 11×φ18 | 17xφ16 | φ128-12 | 58.0 | KQZG-254P2 |
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Our drill bits are made from high-quality alloy steel and subjected to rigorous heat treatment to achieve high hardness, superior wear resistance, and excellent impact resistance. This ensures top performance in complex and variable drilling environments, significantly extending service life.
·Spherical Buttons: Designed with a robust spherical structure, these inserts are ideal for hard, abrasive rock formations and deep-hole drilling. Their versatility makes them a preferred choice for almost all rock drilling applications, from mining to foundation engineering, ensuring exceptional drilling efficiency and stability.
·Semi-Ballistic Buttons: A hybrid design that balances speed and durability. Compared to traditional spherical buttons, semi-ballistic inserts offer faster penetration rates and extended service life, particularly suitable for medium to low-abrasion sedimentary rock layers. However, they are not recommended for fractured ground conditions to maintain optimal drilling performance.
·Ballistic Buttons: Engineered for high-speed drilling in low-abrasion sedimentary deposits. Its high-efficiency cutting ability greatly enhances drilling efficiency, especially for applications where rapid penetration is required. However, it is not recommended for use on severely broken ground or extremely hard rock to avoid unnecessary wear and performance degradation.
Our tungsten carbide inserts are embedded into the drill bit head using a precision cold-press or hot-insertion process, ensuring a firm bond between the inserts and the skirt body. It improves the overall strength and stability, making the drill bit more durable, reducing replacement frequency, and lowering drilling costs.
Choose a drill bit with a high-strength skirt body and spherical drill bits. The number of flushing grooves should be limited (typically a two-wing bit), and their size should not be too large to optimize efficiency. It is better to choose the spherical button for the carbide buttons, and the exposed height of the spherical button should not be too large.
Opt for a drill bit with enhanced cuttings removal capability, such as a three-wing or four-wing bit. The flushing grooves can be larger and deeper to facilitate debris removal. Inserts should be ballistic or wedge-shaped, with a higher profile for improved penetration.
To minimize deviation, use a concave or convex bit face for better guidance and stability.
The middle slag discharge hole is often blocked, it is best to use the side slag discharge bit.
Ensure the drill bit size matches the DTH hammer and drill pipe dimensions. The maximum drill bit diameter is one inch larger than the hammer size.
Larger hole diameters require larger drill bits. The deeper the drilling depth, the higher the requirements for wear resistance and stability of the drill bit.
The penetration rate depends on the drill bit type, rock hardness, and operational parameters. Choose a drill bit that can achieve the desired drilling speed under the given conditions.
A crucial factor in drill bit performance, efficient cuttings removal reduces resistance and increases penetration speed. We pay attention to the flushing groove design and how effectively it clears debris.
Beyond the initial purchase price, consider the maintenance and replacement costs. Durable drill bits reduce the frequency of replacements, ultimately lowering operational costs over time.
Choosing a trusted brand with quality service minimizes risks and improves value for money.
These parameters should match the drilling rig’s specifications to ensure optimal performance.
The drill bit’s material composition and production process directly affect performance and lifespan. These parameters should be determined based on the specific rock drilling equipment and process requirements.
Through rigorous quality control at every stage, Kelleg guarantees that our drill bits and other rock drilling tools meet the highest industry standards, delivering exceptional performance, reliability, and durability to our customers.
