A tricone bit drills with three rotating cones that crush and gouge the rock. It is still the standard choice for large hole sizes and for hard or broken formations where a fixed-cutter bit struggles. Ironstone sources tricone bits — both tungsten-carbide insert (TCI) and milled-tooth — from qualified manufacturers, matched to your formation and delivered CFR your port.
The IADC code is a three-digit system that classifies roller-cone bits so bits from different makers can be compared. Reading left to right:
| Digit | What it describes |
|---|---|
| First (1–8) | The cutting structure series. Series 1–3 are milled-tooth bits, running soft to hard rock. Series 4–8 are tungsten-carbide insert (TCI) bits — and the hardness scale restarts at soft: series 4 is a very soft TCI bit, series 8 extremely hard. |
| Second (1–4) | A finer division of formation hardness within the first digit's range — 1 is the softest, 4 the hardest, in that band. |
| Third (1–7) | The bearing and gauge design — for example sealed roller bearings, sealed friction bearings, and gauge protection features. |
So a code like 537 points to an insert bit for a particular formation-hardness band with a particular bearing and gauge design. Tell us the code you run today, or just the formation, and we match it.
| Type | Best for | Note |
|---|---|---|
| Milled tooth (steel tooth) | Soft to medium formations — clays, shales, soft sands. | Lower cost; teeth wear faster, so best where footage is high and rock is not too hard. |
| TCI (tungsten-carbide insert) | Medium-hard to very hard formations — hard sandstone, limestone, dolomite, and abrasive rock. | Higher cost and longer life in hard rock; insert shape is matched to hardness. |
Each bit size pairs with a standard pin connection so it fits the bit sub and drill string. Larger bits use larger API Regular connections; smaller bits step down through the standard sizes. The full mapping is in our bit size to API connection chart. Because a mismatch stops the job, state your hole size and current connection when you inquire and we confirm the pairing on the quotation, or send your bit details on WhatsApp and we confirm the match.