Types of Self-Drilling Rock Bolt Drill Bits and Applicable Geological Conditions

The drill bit is an important part of the self-drilling rock bolt, and it is a necessary condition for the integration of the three functions of drilling, grouting, and anchoring. Without the drill bit, it is impossible to realize the function of self-drilling. So, what are the types of self-drilling rock bolt bits? What geological conditions can they be used in? Today, Sinorock will take everyone to learn together.

self drilling rock bolt system

Drill Bits Processing Technology

Self-drilling hollow bolt bit, according to different types, generally adopts a casting or machining process.

Type of Drill Bits

There are many types of self-drilling hollow bolt bits, and you can choose different bits according to different geological conditions. Below Sinorock introduces some commonly used drill bits for you.

Hardened Drill Bits

Hardened Cross-cut Drill Bit (EX)

Applicable geological conditions: mudstone, gravel soil, chalk soil, lime soil, calcareous clay, artificial fill, soft mudstone.

Hardened Button Drill Bit (ES-F)

Applicable geological conditions: crushed formation, soft sandstone, limestone, gravel, soft rock formation.

Clay Drill Bit

Applicable geological conditions: clay, soft soil, sandy soil, gravel, mixed fill.

Carbide Drill Bits

Cross Carbide Drill Bits

Applicable geological conditions: soft to medium hard rock, such as gravel mixed with boulders, rock formations with developed cracks, and unreinforced concrete.

Carbide Button Drill Bit

Applicable geological conditions: soft to medium hard weathered rock formations, boulders, gravel, such as mudstone, schist, volcanic rock, etc.

rock bolt drill bits

Drill Bit Structure

Different types of drill bit structures are naturally different, and different structures will have an impact on the drilling efficiency during construction. We take the cross alloy drill as an example to illustrate its structural characteristics.

The cross alloy drill is composed of five parts: the cross blade, the upper and lower slag discharge grooves, the neck of the trousers, the flushing hole or the slurry hole. The cross-blade is used to break the rock; the upper and lower slag discharge grooves are used to discharge the broken slag after the rock is broken; the neck of the trousers has internal threads, which are used to connect with the hollow bolt; the functions of the flushing hole or the slurry hole are: The two are used as air or water channels during drilling to discharge the debris in the hole, and used as a slurry channel during grouting, and the slurry is injected into the hole by pressure grouting.

At the same time, there are two more important parameters of the cross alloy drill, that is, the edge angle and the clearance angle. The smaller the blade angle, the faster the drilling speed, but it is not wear-resistant, which is more suitable for the rock formation with softer geology; the larger the blade angle, the slower the drilling speed, wear-resistant, and suitable for hard rock formations. If the clearance angle is too small, it is easy to cause sticking when drilling, and if it is too large, it is easy to wear.

Common Problems and Solutions

Hardened Drill Bits

Drill Bit Broken

Cause analysis: During the heat treatment process, crack defects are generated, or the structural design has stress concentration defects.

Solution: strictly control the heat treatment process or optimize the structural design.

Low Drilling Efficiency or Short Service Life

Reason analysis: unreasonable structural design or poor heat treatment hardness control.

Solution: Strictly control the heat treatment process or optimize the structure design of the drill bit.

Carbide Drill Bits

Damaged Alloy Teeth

Cause analysis: cracks in welding or improper operation

Solution: Rework Soldering

Shorter Service Life

Reason analysis: unreasonable structural design of alloy drill trousers

Solution: optimize the structural design.

Rock Bolt Drill Bit and Applicable Geological Condition

The above is the introduction of the various types and application scope of self-drilling hollow bolt bits. Sinorock believes that through the above introduction, everyone will have a certain understanding of drill bits. If you have any questions about the self-drilling rock bolt bit, you are welcome to contact us by email at any time, and we will give you the most professional answer as soon as possible.

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