Boost Performance • Extend Service Life • Reduce Drilling Cost
Down-the-hole (DTH) hammers are core components in mining, quarrying, geotechnical drilling and water well drilling. Proper maintenance directly determines their penetration rate, air consumption, and long-term reliability. This guide provides a complete, practical, field-proven DTH hammer maintenance method that your drilling team can follow every day.
To help readers explore related systems, this guide naturally references different DTH hammer categories such as Low Pressure DTH Hammer, Medium Pressure DTH Hammer, and High Pressure DTH Hammer, as well as the extended article "How to Choose the Right DTH Hammer."
Why DTH Hammer Maintenance Matters
A well-maintained DTH hammer can:
Improve drilling efficiency by 15–30%
Reduce fuel and air compressor cost
Extend hammer life by 40–60%
Prevent unplanned downtime
Protect drill pipes, bits, and other high-value components
If you use different hammer types, you can also refer to:
Daily Maintenance Routine (Before Drilling)
Before each shift, operators should conduct a systematic inspection:
2.1 Check the Air Supply System
●Ensure the compressor reaches the required operating pressure.
●Low-pressure hammer users can refer to recommended operating ranges here: Low Pressure DTH Hammer
●Inspect moisture content in the air - excessive water accelerates rust and internal wear.
2.2 Inspect Hammer Threads and Connections
●Clean all API threads.
●Apply thread grease evenly.
●Confirm the sub adaptor is tightly secured.
2.3 Choose the Correct Bit
Bit selection affects energy transfer efficiency.
Refer to: "How to Choose the Right DTH Hammer"
3. Maintenance During Drilling
3.1 Keep the Hammer Well-Lubricated
DTH systems need continuous lubrication to reduce wear on moving components such as the piston and internal sleeves.
●Use a reliable in-line oiler.
●Recommended: 0.1–0.2 L of rock drill oil per hour for low-pressure systems.
3.2 Monitor Penetration Rate Changes
A sudden drop in ROP (rate of penetration) usually indicates:
●Worn-out bit
●Insufficient lubrication
●Air pressure fluctuations
●Internal piston friction
4. Maintenance After Drilling
Run air through the hammer for 15–20 seconds with the bit raised above the hole bottom.
Wipe down the piston, bit chuck, wear sleeve, and internal splines.
Remove mud, sand, or rock fines.
5.Periodic Maintenance (Every 300–500 meters or 40–60 hours)
We offer a variety of transmission components
5.1 Complete Disassembly
Fully dismantle the hammer:
- Piston
- Bit retaining rings
- Wear sleeves
- Check valves
- O-rings
- Top and bottom sub
5.2 Inspect Wear Conditions
- Replace immediately if you observe:
- Surface scoring on piston
- Crack on sleeves
- Deformation of chuck
- Hardening or flattening of O-rings
- Excessive wear around bit splines
6. Choosing the Right Lubricant
Lubrication directly determines hammer life.
Recommended rock drill oils:
ISO VG 100 / VG 150 (low pressure)
ISO VG 150 / VG 220 (medium pressure)
High-viscosity synthetic oils for high pressure
For more technical guidance, refer to the article: "What Is a DTH Hammer and How It Works?"
7. Storage & Long-Term Protection
When the hammer is not in use:
Apply rust preventive oil
Seal both ends with protective caps
Store in a dry environment
Rotate stored components every two months to prevent sticking
8. Troubleshooting Common Issues
Hammer does not start
- Check air pressure
- Clean check valve
- Verify bit is not jammed
Slow penetration rate
- Worn-out bit
- Insufficient lubrication
- Air leakage through threads
Excessive air consumption
- Internal sleeve wear
- Piston sealing failure
- Bent or worn bit splines
Conclusion
Following this maintenance guide will:
Maximize hammer performance
Reduce air & fuel consumption
Prevent expensive downtime
Extend the service life of bits, hammers and drill rods
Lower total drilling cost per meter
Consistent maintenance is the most cost-effective way to protect your drilling investment-especially when using high-efficiency systems like Dminingwell low-, mid-, and high-pressure DTH hammers.
