Imagine a drilling team working on a hillside quarry where the final hole depth must reach strict measurement requirements. In this scenario, dth hammers and bits become essential tools for maintaining hole straightness and ensuring consistent drilling results. However, many operators still face accuracy challenges caused by geological variations, equipment vibration, or uneven wear on the DTH hammer button bits.

Many users ask: Why does hole deviation occur even when using high-quality tools? The answer often lies in the complex interaction between the hammer, bit design, air system, and drilling technique.

1. How Bit Design Shapes Drilling Accuracy

The structure of a DTH bit—carbide shape, face design, and gauge layout—has a direct impact on hole straightness. When the bit face is not properly matched to the formation, deviations may become more noticeable as drilling progresses.

Key design factors affecting accuracy:

Gauge button size and distribution determine how well the bit maintains its path.

Face shape (flat, concave, convex) influences stability.

Carbide type affects resistance to deformation under high impact.

A concave face design is popular for straightness because it naturally centers the bit during penetration. In contrast, a convex face may generate faster penetration in soft rock but can drift in fractured formations.

Recommendation:

Work closely with technical guides to select the proper face structure before starting drilling, especially in stratified rock layers.

2. Impact Energy Stability and Its Effect on Hole Path

A stable hammer delivers consistent impact energy, which is critical for accurate drilling. Fluctuating impact force can cause the bit to “wander,” especially in formations with mixed hardness.

What causes instability?

Irregular air pressure

Worn internal hammer components

Accumulation of cuttings

Bent drill rods

How to improve stability:

Ensure the compressor provides constant airflow

Inspect the hammer regularly

Replace worn drill rods immediately

3. Influence of Bit Wear on Hole Deviation

As dth hammer button bits wear down, especially the outer gauge buttons, accuracy begins to decrease. The bit gradually loses its ability to guide itself vertically, causing deviation.

Common signs of accuracy loss due to wear:

The hole becomes wider at the top

Penetration slows down without clear cause

The drill string vibrates more than usual

Suggested maintenance approach:

Replace the bit once gauge wear reaches the manufacturer’s limit

Use wear-resistant carbide buttons in abrasive rock

Keep drilling logs to track wear patterns

4. Drilling Technique: Operator Influence on Accuracy

Even with high-quality tools, drilling accuracy still depends heavily on how the operator handles the rig. Excessive feed force or poor alignment during the initial collaring can result in deviations that increase with depth.

Operator practices that improve accuracy:

Start drilling slowly to establish a centered collar

Use proper feed force—neither too aggressive nor too light

Keep rig alignment within recommended tolerance

Monitor vibration changes during drilling

5. Geological Factors and How to Adapt to Them

Different formations challenge drilling accuracy in different ways. Layered or fractured rock can redirect the bit, while extremely hard rock may cause excessive vibration.

To maintain accuracy in complex geology:

Use bits with reinforced gauge rows

Increase flushing air to stabilize the hole bottom

Slow down rotation in fractured zones

Adjust hammer size if the existing tool struggles to maintain direction

With advanced manufacturing technology and a deep understanding of drilling dynamics, Kaiqiu Drilling Tools Co., Ltd. provides reliable DTH solutions that help operators obtain more precise results in demanding environments.