Reaming Bits for Rock Drilling
Reliable reaming bit solutions for enlarging pre-drilled pilot holes in mining, tunneling, quarrying, anchoring, and other rock drilling applications. Choose from integral reaming bits or combination reaming systems based on hole depth, formation conditions, and drilling requirements.
Two Reaming
Solutions
Integral reaming bits
and combination reaming
systems for different drilling requirements.
Multiple Diameters & Threads
Available in
different diameters and thread connections to match your drilling system.
Stable
Rock Breaking
Carbide button configurations designed for
efficient rock breaking and wear resistance.
Application-Specific Selection
Select the appropriate reaming solution based on hole depth, rock formation, and drilling requirements.
Reaming Bits Designed for Efficient Hole Enlargement
Kelleg reaming bits are designed for top hammer rock drilling applications where an existing pilot hole needs to be enlarged to the required final diameter. The reaming structure works together with the pilot hole to provide controlled hole enlargement while maintaining drilling stability.
Our reaming bit range includes integral reaming bits and combination reaming systems. Integral designs are the more commonly used option and are available in mushroom-type and pilot-post configurations. Combination systems use a separate reaming bit and pilot guide for applications requiring a more flexible configuration.
Remaining Bit Types for Different Drilling Requirements
Reaming bits can be broadly classified into two structural configurations: integral reaming bits and combination reaming systems. Integral reaming bits combine the reaming and guiding structure into one tool, while combination systems use a separate reaming bit and guide.
For most conventional rock drilling applications, integral reaming bits are the more commonly used choice. Combination systems are mainly selected for specialized deep-hole, long-hole, or demanding drilling conditions.
Integral Reaming Bits
An integral reaming bit combines the reaming body and guiding structure into a single tool. This simplifies installation and operation and eliminates the need to assemble separate guiding components.
- Simple
- Lightweight
- Cost-Effective
Dome Reaming Bit (Mushroom-type Reaming Bit)
The dome reaming bit features a compact one-piece design without a separate guiding column. Its lightweight structure makes it easy to handle and install, making it a practical choice for shallow-hole reaming and relatively uniform rock formations.
Key Advantages:
- One-piece construction
- Lightweight and easy to handle
- Simple installation and replacement
- Cost-effective tooling solution
- Efficient for shallow-hole reaming
- Suitable for relatively uniform formations
- Stable Guidance
- Better Alignment
- Deep-Hole Applications
Pilot Reaming Bit
The pilot reaming bit integrates the guiding post and reaming body into a single tool. The pilot enters the existing pilot hole and helps guide the reaming bit during operation, improving drilling stability and helping reduce hole deviation in medium- and deep-hole applications.
Key Advantages:
- Integrated pilot and reaming structure
- Stable guidance during reaming
- Improved hole alignment
- Helps reduce deviation in deeper drilling
- No separate guide assembly required
- Convenient for routine drilling operations
Combination Reaming System
A combination reaming system consists of a reaming bit and a pilot adapter. The guide follows the existing pilot hole while the reaming bit enlarges the hole to the required diameter.
Compared with integral designs, the combination configuration provides greater flexibility for certain specialized drilling conditions and allows individual components to be replaced separately.
Key Advantages:
- Separate reaming bit and pilot adapter
- Modular configuration
- Flexible component replacement
- Suitable for specialized deep-hole applications
- Potentially lower long-term tooling replacement costs in suitable applications
- Adaptable to specific drilling requirements
Combination reaming systems are used less frequently than integral reaming bits and are generally selected when their modular configuration provides a specific advantage for the drilling application.
Compare Reaming Bit Configurations
For most standard rock drilling applications, integral reaming bits provide a simple and efficient solution. Combination systems are generally considered when deep-hole length, formation complexity or component-level flexibility becomes a key requirement.
| Feature | Dome Reaming Bit | Pilot Reaming Bit | Combination System |
|---|---|---|---|
| Structure | One-piece | One-piece with integrated pilot | Separate reaming bit + pilot adapter |
| No separate pilot post | Integrated pilot post | Separate pilot guide | |
| Installation | |||
| Lightweight | Moderate | Depends on configuration | |
| Guiding Stability | Suitable for general shallow-hole applications | Improved guiding stability | Depends on pilot configuration |
| Hole Depth | Shallow-hole applications | Medium- and deep-hole applications | Specialized deep/long-hole applications |
| Rock Conditions | Relatively uniform formations | Various rock conditions | Fractured / alternating formations |
| Replacement | Complete tool replacement | Complete tool replacement | Individual components can be replaced |
| Typical Use | Shallow-hole support, quarrying, blasting | Tunnel anchoring, underground mining | Ultra-long holes, specialized projects |
| Usage | Common | Common | Less common |
How Does a Pilot Reaming Bit Work?
Step 1 Drill the Pilot Hole
A smaller-diameter drill bit creates the initial pilot hole to establish the required drilling direction.
Step 2 Engage the Reaming Bit
The pilot section or guide enters the existing pilot hole and guides the reaming operation.
Step 3 Enlarge the Hole
The reaming buttons break the surrounding rock as the tool rotates and impacts, enlarging the pilot hole to the required final diameter.
Step 4 Complete the Final Hole
The resulting hole reaches the specified diameter for anchoring, blasting, drainage, mining, or other drilling purposes.
Want to learn more about reaming bit types, applications, and selection? Read our complete guide to reaming bits.
Reaming Bit Specifications
Reaming bit performance depends on the correct combination of diameter, thread, pilot size, carbide button configuration, and drilling application. Select a configuration that matches your existing drilling system and required final hole size.
| Thread | Bit Dia. | No.×Button Dia. | Flushing Hole | Weight (kg) | ||||
| mm | inch | Front | Gauge | Angle | Front | Side | ||
| Spherical Buttons/ Parabolic Buttons | ||||||||
| R32 | 76 | 3 | 1×13 | 9×13 | 35° | 3 | 1 | 2.0 |
| 89 | 3 1/2 | 1×13 | 14×13 | 35° | 2 | 2 | 2.6 | |
| 102 | 4 | 1 ×13 | 16×13 | 35° | 2 | 2 | 3.2 | |
| 127 | 5 | 1×13 | 18×13 | 35° | 3 | 1 | 4.8 | |
| T38 | 102 | 4 | 1×13 | 16×13 | 35° | 2 | 2 | 3.8 |
| 127 | 5 | 1×13 | 18×13 | 35° | 1 | 3 | 5.2 | |
| T45 | 127 | 5 | 1×13 | 18×13 | 35° | 3 | 1 | 6.0 |
| 152 | 6 | 2×14 | 18×14 | 35° | 3 | 1 | 10.6 | |
| T51 | 152 | 6 | 2×14 | 18×14 | 35° | 3 | 1 | 10.6 |
| ST58/ST68 | 152 | 6 | 6×16 | 9×16 | 35° | 3 | — | 13.0 |
| 152 | 6 | 2×14 | 18×14 | 35° | 3 | 3 | 10.4 | |
| Thread | Bit Dia. | No.×Button Dia. | Flushing Hole | Weight (kg) | ||||
| mm | inch | Front | Gauge | Angle | Front | Side | ||
| R25/R28/R32 | 64 | 2 1/2 | 2×10 | 8×9 | 35° | – | – | 0.8 |
| 64 | 2 1/2 | 4×8 | 8×9 | 25° | – | – | 0.8 | |
| 76 | 3 | 2×11 | 8×11 | 35° | – | – | 1.2 | |
| 76 | 3 | 4×10 | 8×10 | 30° | – | – | 1.2 | |
| 89 | 3 1/2 | 4×11 | 8×11 | 35° | – | – | 1.7 | |
| 89 | 3 1/2 | 4×10 | 8×10 | 30° | – | – | 1.7 | |
| R32 | 89 | 3 1/2 | 4×10 | 8×12 | 35° | – | – | 1.8 |
| 102 | 4 | 4×12 | 8×12 | 35° | – | – | 2.1 | |
| 127 | 5 | 4×12 | 8×12 | 35° | – | – | 4.0 | |
| 127 | 5 | 4×13 | 8×13 | 35° | – | – | 4.0 | |
| Thread | Bit Dia. | No.×Button Dia. | Flushing Hole | Weight (kg) | ||||
| mm | inch | Front | Gauge | Angle | Front | Side | ||
| R25 Pilot Adapter 6° | 26 | 1 1/32 | 12×8 | – | – | – | 1.3 | |
| R28 Pilot Aapter 6° | 26 | 1 1/32 | 12×8 | — | — | — | 1.5 | |
| R32 Pilot Adapter 12° | 40 | 1 37/64 | 15×10 | – | – | – | 2.2 | |
We can supply reaming bits in different thread and diameter configurations to match your existing drill rods, drilling equipment, and required hole size.
Thread Options:
R25 | R28 | R32 | R38 | T38 | T45 | T51 | ST58 | ST68 | [Others]
Diameter Range:
[64–152 mm]
Custom Sizes:
Available according to project requirements.
Carbide Button Configuration for Rock Drilling
The carbide button configuration plays an important role in reaming performance. Button shape, size, layout, and carbide grade should be selected according to rock hardness, abrasiveness, and drilling conditions.
Kelleg can configure the cutting structure according to the required drilling application, balancing penetration performance, gauge protection, and wear resistance.
Button Shape
Select a suitable carbide button profile according to formation hardness and drilling requirements.
Button Layout
Optimized face and gauge button distribution helps maintain effective rock breaking and hole diameter.
Carbide Grade
Carbide selection is matched to the required balance between impact resistance and wear resistance.
Why Choose Kelleg Reaming Bits?
Designed for Your Drilling Conditions
Reaming bit configuration can be selected according to hole diameter, drilling depth, rock formation, drilling equipment, and connection requirements.
Wear-Resistant Carbide Buttons
Carefully selected carbide buttons are designed to withstand repeated impact and abrasive rock conditions.
Stable Hole Enlargement
Appropriate pilot and reaming geometry helps maintain stable guidance and consistent hole enlargement.
Accurate Thread & Dimensions
Controlled machining and dimensional inspection help ensure reliable compatibility with the drilling system.
Application-Based Recommendations
Our technical team can recommend a suitable configuration based on your drilling parameters rather than simply supplying a standard bit.
OEM & Customized Options
Diameter, thread, button configuration, and other product parameters can be customized according to project requirements.
Reaming Bit Manufacturing & Quality Control
Consistent reaming performance starts with controlled manufacturing. Each reaming bit requires accurate machining, reliable heat treatment, secure carbide button installation, and dimensional inspection.
Dimensional Accuracy
Thread Inspection
Carbide Button Retention
Final Visual Inspection
Applications
Reaming bits are essential for mining, tunneling, raise boring, and water well drilling operations. Designed to enlarge existing pilot holes to the targeted diameter with precision, they maximize drilling efficiency, ensure superior hole straightness, and reduce overall tool wear—delivering cost-effective performance in complex rock formations.
How to Choose the Right Reaming Bit
Selecting the ideal reaming bit depends on balancing your rock hardness, required hole diameter, and drilling equipment.
Reaming Bit vs. Standard Rock Drill Bit
A reaming bit is not simply a larger standard drill bit. It is designed specifically to enlarge an existing pilot hole while maintaining controlled guidance during the reaming process.
| Feature | Standard Rock Drill Bit | Reaming Bit |
|---|---|---|
| Main Function | ||
| Starting Condition | Solid rock | Existing pilot hole |
| Typical Role | Initial drilling | Secondary hole enlargement |
| Guiding Method | Drill bit geometry | Pilot hole / guide structure |
| Main Objective | ||
| Typical Use |
Common Reaming Bit Problems and Solutions
Rapid Button Wear
Possible Causes:
- Highly abrasive rock
- Unsuitable carbide configuration
- Excessive drilling parameters
- Inadequate flushing
Review rock conditions, button configuration, drilling
Hole Diameter Becomes Undersized
Possible Causes:
- Gauge button wear
- Incorrect bit selection
- Excessive wear during long drilling cycles
Check gauge button condition and confirm that the selected reaming diameter matches the required final hole size.
Hole Deviation
Possible Causes:
- Pilot hole deviation
- Insufficient guiding stability
- Rod deflection
- Complex geological conditions
Check the pilot hole and drilling system, and consider a pilot-post configuration when improved guidance is required.
Reaming Bit Gets Stuck
Possible Causes:
- Poor flushing
- Cuttings accumulation
- Fractured or unstable formation
- Hole deviation
Review flushing, drilling parameters, and hole condition before continuing operation.
Need Help Selecting a Reaming Bit?
Selecting a reaming bit based on diameter alone may result in poor compatibility or unnecessary wear.
Please provide:
- Drill Rig Model
- Drill Rod Thread
- Pilot Hole Diameter
- Final Hole Diameter
- Drilling Depth
- Rock Type
- Application
Get in Touch with Us Anytime!
Our technical team can help match the reaming bit configuration to your drilling system and project conditions.
Related Top Hammer Drilling Tools
Explore our complete range of top hammer drilling tools for different drilling methods and rock conditions.
Top Hammer Drill Bits
Explore versatile rock drill bits, including Cross and Button Bits, with threaded bit, retrac bit, and reaming bit options for efficient drilling across diverse rock formations.
Drill Rods
Choose from tapered rod, shank rod, integral rod, and heavy-duty drill rods, engineered for reliable drilling performance in mining, tunneling, excavation, and open-pit operations.
Shank Adapters
Manufactured from high-quality steel, our shank adapters deliver high strength, toughness, and wear resistance for reliable performance in demanding drilling conditions.
Coupling Sleeves
Available in full-bridge and reducing designs, our coupling sleeves provide reliable rod connections for drifting, deep-hole drilling, and demanding rock drilling applications.
Threaded Button Bits
Designed for general geological conditions, threaded button bits feature evenly distributed carbide buttons for reliable penetration across a wide range of rock hardness levels.
Retrac Button Bits
Designed for loose and fractured formations, retrac button bits improve tool retrieval, reduce jamming risks, and help maintain straighter holes in mining and tunneling.
Tapered Drill Bits
Built with premium carbide inserts and robust steel bodies, our tapered drill bits deliver reliable penetration and durability in 7°, 11°, and 12°.
Cross Bits
Featuring multiple carbide blades in a cross-shaped design, our cross bits deliver efficient rock breaking and reliable drilling performance across demanding formations.
Frequently Asked Questions
A reaming bit is used to enlarge an existing pilot hole to a larger final diameter. It is commonly used in rock drilling applications such as mining, tunneling, anchoring, quarrying, and specialized long-hole drilling.
Reaming bits can generally be divided into integral reaming bits and combination reaming systems. Integral reaming bits include dome reaming bit and pilot reaming bit, while combination systems use a separate reaming bit and pilot adapter.
A mushroom-type reaming bit has a simple one-piece configuration without a separate pilot post and is commonly used for shallow-hole applications. A pilot reaming bit integrates a guiding post into the tool and provides improved guidance for medium- and deep-hole drilling.
A combination reaming system consists of a separate reaming bit and pilot adapter. It provides a modular configuration and is mainly used for specialized deep-hole or long-hole applications.
For medium- and deep-hole applications where guiding stability is important, a pilot reaming bit is often a suitable choice. For specialized ultra-long or complex drilling applications, a combination system may provide additional flexibility.
The final reaming diameter should be determined by the required final hole size. The pilot diameter, drilling system, rock formation, and drilling depth should also be considered.
Please provide the pilot hole diameter, final hole diameter, thread, drilling depth, rock type, drill rig model, and application. This information helps us recommend a suitable configuration.
Yes. Reaming bits can be customized according to required diameter, thread, pilot configuration, carbide button arrangement and other project-specific requirements, subject to technical evaluation.
Use a configuration suitable for the rock formation, maintain appropriate drilling parameters, ensure effective flushing, and monitor gauge and carbide button wear during operation.
