In HDD projects, many drilling problems are not caused by equipment—but by incorrect bit design.
Common issues include:
These problems are directly related to blade count, cutter size, and back rake configuration.
More blades (5–7 blades):
Fewer blades (3–4 blades):
Large cutters (16–19mm):
Small cutters (13mm):
Back rake is the angle between the cutter face and the formation.
Low back rake (aggressive angle):
High back rake (conservative angle):
| Formation | Blade Count | Cutter Size | Back Rake |
|---|---|---|---|
| Soft Soil | 3–4 | 16–19mm | Low |
| Medium Rock | 4–5 | 13–16mm | Medium |
| Hard Rock | 5–7 | 13mm | High |
Back rake is the angle between the cutter face and the formation.
Low back rake (aggressive angle):
High back rake (conservative angle):
Blade count, cutter size, and back rake directly determine HDD drilling performance.
Choosing the right configuration can:
Looking for the right HDD PDC bit for your project? Contact us with your rock type, formation details and drilling conditions.
[ PDC Drill Bit for Hard Rock and Directional Drilling – Buyer’s Guide ]
It depends on formation. Hard rock typically requires more blades.
No. They drill faster but wear faster.
It depends on formation hardness.
No. Different formations require different designs.
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