Many users frequently ask why certain DTH hammer button bits experience premature breakage, cracking, or uneven wear. These issues directly affect performance and increase operating costs, especially in challenging geological formations.

As a professional manufacturer of high-end rock drilling tools, Kaiqiu Drilling Tools Co., Ltd. has long been engaged in the research, development, and manufacturing of DTH hammers and bits. With years of field testing and technical support experience, the company has summarised the more common causes of button bit failures.

1. Incorrect Bit Selection for the Rock Formation

One of the primary reasons for button bit damage is choosing a bit that does not match the hardness or abrasiveness of the formation.

Typical scenarios include:

Using ballistic buttons in very hard or abrasive rock

Selecting spherical buttons for softer formations where high penetration is needed

Choosing wrong face design when encountering fractured rock

Ballistic buttons offer fast penetration but are not ideal for extremely hard rock. They may chip or crack under heavy impact. Conversely, spherical buttons provide higher wear resistance but result in slower drilling if used in soft formations.

Solution:

Match bit design and carbide shape with geological conditions

Consult suppliers or technical guides when drilling in mixed formations

Test multiple configurations to determine the suitable design

2. Excessive Rotation Speed

Excessive rotation is a common operational mistake that leads to severe wear or breakage. When the bit rotates too quickly, the carbide buttons are forced to scrape rather than impact the rock, increasing the stress on each button.

Symptoms:

Sharp edge cracks

Premature chipping

Excessive gauge wear

Uneven wear patterns

Corrective measures:

Maintain recommended RPM for the specific hammer size

Reduce rotation in extremely hard formations

Ensure rotation torque is stable and not overloaded

3. Insufficient Air Pressure or Poor Air Supply

Air supply is not only responsible for powering the hammer but also essential for removing cuttings. When air pressure fluctuates or falls below the recommended level, cuttings accumulate around the bit face, causing heat buildup and uneven stress on the carbide buttons.

Potential results:

Cracked button tops

Bit face overheating

Stuck bit or severe slowdown in drilling

Recommendations:

Monitor compressor output continuously

Inspect air hoses for leakage

Avoid drilling at low pressure settings

Keep the hammer and bit free of moisture that reduces airflow

4. Drilling at an Incorrect Angle

A misaligned drilling angle puts significant side stress on the bit. Even slight angular deviation can cause the bit to strike the rock unevenly, result in button breakage or body fracturing.

Typical causes:

Poor rig stability

Damaged or worn drill pipes

Ground slippage during operation

Incorrect collaring at the hole’s beginning

Solutions:

Use stabilizers when drilling deep or in broken formations

Ensure the rig is properly leveled

Replace bent or worn drill pipes

Maintain strict control during initial positioning

5. Overdrilling with a Worn Bit

When operators continue drilling with a bit that has reached the end of its service life, the risk of breakage increases significantly. Excessive gauge wear reduces the bit’s ability to stabilize itself, causing vibration, heat, and stress concentration.

Indicators of an overused bit:

Buttons worn down to the body

Cracks forming around the gauge row

Reduced penetration rate

Irregular noise during drilling

Preventive actions:

Replace bits once gauge wear exceeds the recommended limit

Track drilling meters per bit for comparison

Conduct periodic visual inspections during drilling

Kaiqiu Drilling Tools Co., Ltd. continues to support global users by providing high-quality DTH hammers and bits, reliable heat treatment technology, and practical guidance designed to help operators achieve stable, efficient drilling in diverse working environments.