1.  Dented, chipped, or damaged striking end

Probable causes:

- Misalignment from worn out bushings

- Piston damage

Suggested actions:

- Replace worn out components in rock drill, including but not limited to bushings and pistons

2. Failure Across the Splines

Probable causes:

- Bushing wear leading to misalignment

- High rotational torque

- Getting rod stuck in unconsolidated rock or excessive reverse hammering

- Worn chuck coupling

- Inadequate feed pressure

- Drilling with dull bits

Suggested actions:

- Use the proper type and quantity of lubrication, checking often

- Employ retract bits in challenging rock conditions

- Replace worn out chuck coupling

- Modify drilling parameters to match the rock conditions

- Sharpen dull carbides on bit, following correct carbide sharpening procedures

3. Spline shoulder wear on bottom

Probable causes:

- Excessive rotation when retracting the drill string

- Drill rod stuck in unconsolidated rock

Suggested actions:

- Adjust rotational speed to the rock conditions

- Use retract drill bits and a rock drill equipped with a power extractor in tough environments

4. Failure Across the Threads

Probable causes:

- Loose joint connections during drilling

- Poor drilling conditions

- Bending from excessive feed pressure

- Continued percussion with stuck rod in broken rock

- Insufficient thread lubrication

- Non-matching threads

- Drilling with dull bits caused high rotational torque

- Using a worn coupling or drill rod

- Hole deviation

 Suggested actions:

- Modify drilling parameters to match the rock conditions

- Take actions to achieve a straighter hole; use bits with drop center face design and/or retract body

- Ensure joint alignment before threading together

- Change out your couplings with new shank adapters. Use a bridged coupling sleeve

- Sharpen dull carbides, following correct carbide sharpening procedures

- Use thread grease, checking often

- Replace worn-out couplings.

5. Failure at Front Bushing Bearing Surface

Probable causes:

- Misalignment from worn front bushing

- Poor lubrication

Suggested actions:

- Replace worn components

- Ensure proper lubrication

6. Failure through Flushing Port

Probable causes:

- Corrosion from flushing agent

- Dirty flushing water

- Steel fatigue

Suggested actions:

- Replace or maintain flushing agent

- Clean flushing water of solids

- Replace broken, damaged, or worn out drill components

7.  Damaged Thread End

Probable causes:

- Adapter dropped into coupling

- Loose machine cradle

- Boom misaligned

- Adapter not coupled properly to drill rod

- Broken drill rod

- Non-square rod end

Suggested actions:

- Ensure feed mechanism is aligned properly

- Align the boom before drilling

- Replace worn out, damaged, or broken drill rods

- Employ new couplings with new shank adapters

- Regularly inspect condition of drill rod ends

8. Pitting on the threads

Probable causes:

- Unbalanced feed pressure and percussion rate

- Drilling with loose thread joints

- Improper feed to rotation during joint threading

- Insufficient thread lubrication

Suggested actions:

- Monitor joint temperatures; adjust percussion and feed pressures

- Ensure that thread joints are tight before starting percussion.

- Tune feed and rotation to align with thread specifications

- Use thread grease, checking often