Importance of Lubricating Oil for DTH Hammer

Table of Contents

The DTH hammer is a rock drilling equipment widely used in construction engineering, mining, and tunnel construction. During the use of the DTH hammer, insufficient lubricating oil will cause premature wear of the DTH hammer. Therefore, under the premise of correctly selecting and using lubricating oil, it is necessary to keep it internally sufficient.

The functions of lubricating oil in DTH hammer include lubrication, sealing, rust prevention, and heat dissipation. All DTH hammers require lubricating oil to prevent wear, dry friction, and corrosion.

The details are as follows.

1. The high-speed movement of piston of DTH hammer will increase the temperature of lubricating oil, and viscosity of lubricating oil is inversely proportional to temperature.

2. Dry friction will cause piston to heat up rapidly, annealing surface hardened layer to failure, increasing possibility of cracks and piston fracture.

3. Internal parts are covered with a layer of oil film, which can seal the internal clearance, thereby reducing gas leakage and preventing the intrusion of external pollutants.

4. In general, high-pressure gas provided by the air compressor is used as the carrier, and lubricating oil is input to lubricate DTH hammer in a definite proportion. If lubricating oil is not enough, you can pour enough lubricating oil from drill pipe after a sure meter of footage. Adding antioxidants to lubricating oil can form a tight adsorption film on the interface of metal and oil to isolate erosion of water, moisture, and acidic substances. Antioxidants can also prevent the formation of oxidized, acidic oxides and provide significant protection, especially for an unused hammer. In addition, adding wear-resistant agents, antifreeze agents and other unique compounds in particular environments can significantly improve lubrication effect.

DTH hammers

Through the above four points, we can see that lubricating oil is very important for DTH hammer. For use of lubricating oil, expand following 3 points for everyone.

1. Lubricant injection volume

For dry drilling (water injection is less than 7.6LMP), it is usually recommended 2.8mm³/mm air and 0.16L lubricant injection per hour. Leakage and oil loss caused by water requires additional lubricating oil to compensate. More lubricating oil injection is also required when there is foam around the borehole.

2. Lubrication device

There are two main types of lubricating devices, tube oilers, and venturi oilers

Tube oilers are usually achieved with a timed oiling system, which performs oiler by releasing a fixed “metal block” at a fixed time. The advantage of oiling system is that lubricating oil does not require particularly high pressure.

Venturi oiler works in a similar way to a gasoline carburetor. Venturi reduces pressure by contracting small holes, which vaporize oil.

3. Lubrication detection

When lubricating oil is filled into air stream with a dry hard pipe or hose, it will take a large amount of oil to wet pipe wall before oil can pass into the DTH hammer. Before the tube wall is not covered with an oil film, virtually no oil is transmitted to hammer. Therefore, before starting hammer, it is necessary to ensure that there is an appropriate amount of oil film in the pipeline. It is recommended that drill be idled before drilling to determine form of visible oil film before drilling. Use a small piece of cardboard or a small board under drill bit to test hammer for proper lubrication. Especially if hammer has not been used for a long time, you can use the airflow to blow the impactor first and then introduce a sufficient amount of lubricating oil directly from the drill pipe.

How to choose a lubricant?


Choosing lubricants from well-known brands can ensure product quality and after-sales service. They have extensive experience in lubricant R&D and production and can provide products with reliable quality.


Different types of lubricants are suitable for different application scenarios and equipment. When selecting lubricating oil, it is necessary to choose the appropriate lubricant oil according to factors such as the DTH hammer’s model, purpose, and use environment. For example, for severe working conditions with high temperatures and high load, it is necessary to choose lubricating oil with higher viscosity and better high-temperature resistance.

Scope of use

Different lubricants have different application ranges. If we use the wrong lubricating oil, it may cause damage to the equipment or affect its performance.


Viscosity is an essential indicator of the thickness of lubricating oil. Lubricants with different viscosities are suitable for various equipment and operating environments. When selecting lubricating oil, it is necessary to choose the appropriate viscosity based on the DTH hammer’s actual working conditions and needs. If the viscosity is too high, it may lead to increased resistance and energy consumption; if the viscosity is too low, it may not be able to form an efficient protective film on the surface of the parts, affecting the lubrication effect.

Now, the number of DTH hammers used by construction units is increasing day by day. While working efficiently, reliability and long service life can reflect its advantages. However, the working environment of DTH hammer and drill bit in all industrial equipment is particularly harsh, and the working process is uncontrollable. Therefore, it is important to ensure material and processing quality of each part of DTH hammer, and ensure that it has good lubrication conditions to significantly improve the efficiency, stability, and service life.

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