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Best Practices for Maintaining DTH Hammers and Drill Bits

Table of Content

The Introduction

DTH hammers and drill bits can be essential tools for foundation construction, water well, and O&G related drilling industries. However, without proper care and attention, their efficiency and lifespan can decline rapidly. By following the right maintenance practices, businesses can avoid costly replacements and downtime.

In this article, we will cover daily maintenance routines, troubleshooting tips, and key signs of wear to ensure your DTH hammers and drill bits remain in tip top condition.

Understanding DTH Hammers and Drill Bits

What is a DTH Hammer?

A DTH hammer is a pneumatic rotary driven tool used in drilling that works by sending a piston-driven impact force directly on to the carbide face drill bit. It operates using compressed air, making it ideal for drilling in all rock formations, especially harder type ground conditions.

How DTH Drill Bits Work

DTH drill bits are at the very front of the overall drill string and take the brunt and force of the drilling. Attached to the DTH hammer, the drill bit comes in various face designs, including concave, convex, and flat-face configurations. These designs are made to suit different applicational needs. These drill bits pound and fracture rock efficiently, sending the stone chippings up the drilled hole. This method ensures fast penetration rates and minimal energy loss.

Daily Maintenance Tips for DTH Hammers

Cleaning Procedures

Keeping your DTH hammer clean at all times is crucial for preventing hammer performance problems.
  • Remove dust and rock particles after each drilling session.
  • Use compressed air to blow out trapped debris.
  • Apply a mild detergent solution for deep cleaning.
  • Avoid prolonged water exposure to prevent internal rusting.
  • Re-oil hammer internally and immediately after cleaning.

Lubrication Best Practices

DTH hammers require a continuous flow of rockdrill oil especially during operational use. Correct lubrication reduces friction and wear, enhancing the hammer’s lifespan.
  • Use high-quality DTH rock drill oil to ensure smooth piston movement.
  • Ambient drill site temperature should be considered to ensure correct specification oil and viscosity. 
  • Lubricate the hammer before and after each use by pouring in oil through the backhead threaded end.
  • Avoid over-lubrication, as excessive oil can attract dirt and cause clogging.
  • When storing the DTH hammer after cleaning and sufficiently oiled ensure both ends of the hammer are capped each end and layed in the horizontal position.

Routine Maintenance for Drill Bits

Checking for Wear and Tear

Over time, drill bits suffer from steel body erosion, cracks, and flat or part worn carbide inserts. Inspect them regularly to avoid poor drilling efficiency.

  • Check for uneven wear patterns.
  • Replace or refurbish bits showing excessive steel or carbide wear.
  • Ensure plastic foot valves or blow tubes are not chipped, cracked or loose.
  • Keep a log of drilling hours to track tool longevity.

Proper Storage Guidelines

Storage conditions directly impact the lifespan of drill bits.

  • Store bits in a dry, cool environment.
  • Use anti-corrosion coatings for long-term storage.
  • Avoid stacking bits drill face to face as cross carbide inserts contact can lead to breakage or chipping rendering non usable.

Preventative Maintenance for Long-term Performance

Regular Inspections

Routine checks help detect issues before they become major problems.
  • Inspect outer case or wearsleeve for any cracks or heavy wear that could affect performance. Ensure piston moves freely and all rubber or plastic seals are intact hammer components.
  • Check airways are free or dirt and stone chipping that can cause blockages
  • Examine the bit shank for cracks, uneven drive splines and unusual head wear. Also inspect foot valve or blow tube for cracks and loose fitting.

Common Issues and Troubleshooting

Here’s how to handle common DTH hammer problems:

Issue

Cause

Solution




Hammer losing power

Not enough air pressure

Worn drill bit

Worn hammer parts

Too much or not enough oil lubrication

Dirt in hammer or bit

Increase air pressure

Regrind or change bit

Replace worn parts

Check unit oil level, adjust flow

Strip & clean





Inoperative hammer

Drill bit holes blocked

Dirt inside hammer

Worn or damaged parts

Too much or not enough oil lubrication

Hanging internal piston


Insufficient air pressure

Unblock holes

Strip & clean 

Replace damaged parts

Check unit oil level, adjust flow

Piston stuck, clean and polish score marks

Check air pressure & increase operational valve



Low return air velocity (no chippings up hole)

Low air pressure

Insufficient hole flushing or air passing through hammer

Drill bit exhaust holes blocked 

Increase air pressure

Drill or increase choke hole size in hammer


Clean out blockages



Intermittent operation 

Failed, worn or damaged hammer/bit parts

Insufficient oil 

Drill bit broken/damaged

Dirt inside hammer

Overhaul hammer/bit


Check oil lubrication

Replace bit

Strip & clean 

Cost Benefits of Proper Maintenance

Regular maintenance is crucial in:
  • Reduce parts replacement costs
  • Improve drilling accuracy & performance  
  • Minimise costly downtime and delays
A well-maintained DTH hammer and drill bit can last significantly longer, saving thousands in operational costs.

Conclusion

Correct maintenance is key to extending the lifespan of DTH hammers and drill bits. By following regular inspections, cleaning and servicing routines, consistent operational oil lubrication you will ensure peak performance and cost savings in your drilling operations.

FAQs

1. How often should I lubricate my DTH hammer?
During drilling operations it should have a constant flow of oil. Remember hammer oil is the lifeblood of the hammer! When in storage a cup of oil should be poured in the backhead end and in layed in the horizontal position capped at each end to stop direct ingress. This will help against corrosion and is ready to use for your next project.
Use compressed air and mild detergent to remove dirt and debris.
Look for reduced power and increased air consumption. Also as it comes to the end of service life outer components may look deformed or cracked as they have worn.
Improper storage in a vertical or angled position can allow oil to escape and leave open to build up of moisture causing corrosion. The hammer should always be stored horizontally.
Skipping inspections, not cleaning components correctly and improper storage.

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