Drill rod
What is a drill rod?
A drill rod (Drill Rod or Drilling Rod) is one of the essential tools in the drilling industry and is used in various drilling processes, especially in the oil, gas, mining, and tunneling sectors. A drill rod is a long and durable rod, typically made of steel or special alloys, used to transmit the necessary force from the drilling machine to the drill bit and other drilling tools. These rods are designed to withstand high pressure and wear.
The sizes of steel drill rods typically depend on factors such as drilling depth, type of ground, drilling machine, and type of operation. In general, steel drill rods are manufactured in various sizes and dimensions to meet different drilling requirements.
Common sizes of steel drill rods
Steel drill rods are categorized based on diameter, length, and type of connections. Typically, the sizes are as follows:
1.Diameter (Dia) of steel drill rods
The diameter of drill rods usually starts from 2 inches (50.8 mm) and can go up to 6 inches (152.4 mm) or even more in special projects. The diameter of steel drill rods is generally divided into two main categories
Small-diameter rods: between 2 inches and 4 inches (50 to 100 mm) for shallow drilling or softer materials.
Large-diameter rods: between 4 inches and 6 inches (100 to 150 mm) for deeper drilling and harder rocks.
2.Length of steel drill rods:
The length of steel drill rods typically starts from 3 meters (10 feet) and can reach up to 15 meters (50 feet) or more. The rod length depends on project requirements and is usually available in the following sizes:
Short rods: typically have lengths between 3 meters and 6 meters (10 to 20 feet).
Medium rods: typically have lengths between 6 meters and 10 meters (20 to 33 feet).
Long rods: may have lengths over 10 meters (33 feet) and are designed for very deep drilling.
3.Type of connections (Couplings)
Steel drill rods are connected using threaded couplings. The thread sizes and types of connections generally correspond to the rod diameter and the drilling machine. Common types of couplings include:
Straight threads (for simple and quick connections)
Special threads (for higher pressure or hard rock)
Common sizes of steel drill rods:
Here is a general table of typical steel drill rod sizes for reference:
| Rod diameter (inches) | Rod diameter (millimeters) | Rod length (meters) | Usage type |
|---|---|---|---|
| 2″ | 50.8 | 3 – 6 m | Shallow and soft drilling |
| 2.5″ | 63.5 | 3 – 6 m | Small mines or surface structures drilling |
| 3″ | 76.2 | 6 – 10 m | Medium drilling or soft rocky ground |
| 3.5″ | 88.9 | 6 – 10 m | Drilling in medium rocks or more complex structures |
| 4″ | 101.6 | 10 – 15 m | Deeper drilling and hard ground |
| 5″ | 127 | 10 – 15 m | Heavy and deep drilling |
| 6″ | 152.4 | 15 m and above | Ultra-deep drilling in very hard rocks |
To choose the right size of steel drill rod, you should consider the following factors
Drilling depth: the deeper the drilling, the greater the need for longer rods with larger diameters.
Ground type: if the ground is soft, smaller and thinner rods are sufficient, but for harder and rocky ground, larger diameter rods with greater strength are required.
Drilling machine: the rod size must be compatible with the drilling machine and available equipment.
Speed and accuracy requirements: shorter and smaller-diameter rods are usually used for faster drilling, while longer and thicker rods are used for precise and long-term drilling.
Conclusion
The size of a steel drill rod depends on the specific conditions of each project. For drilling in soft and shallow ground, smaller-diameter and shorter rods are used. However, for deeper and rockier drilling, rods with larger diameters and greater lengths are required.