Roller Cone Rock Bits
Three-cone rotary bits with steel teeth or carbide inserts, in open roller and sealed journal bearing designs. The workhorse bit for large-diameter open pit blastholes.
Features
- Sealed journal bearings run at higher weight on bit for longer and cost more; open roller bearings suit lower-cost, lower-duty drilling.
- Steel tooth cutting structures drill soft formations quickly; carbide inserts are needed once the rock becomes hard and abrasive.
- Air courses and nozzle configuration direct flushing air at the cutting structure and keep the bearings cool.
- Bearing failure, not tooth wear, ends most bits, so dull grading at pull-out tells you whether weight and speed were right.
- Gauge protection inserts keep hole diameter, which matters when the hole has to accept a fixed charge diameter.
Specifications
| Figure | Typical range | Unit | Why it matters |
|---|---|---|---|
| Bit diameter | 152 - 406 | mm | Set by the charge diameter in the blast design. |
| Bearing type | sealed journal / open roller | Decides life at the weight on bit actually being used. | |
| Cutting structure | steel tooth / carbide insert | Matched to formation hardness and abrasiveness. |