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 CIF 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 and the formation hardness it is built for — lower numbers for softer rock, higher for harder. The low numbers are milled-tooth bits; the higher numbers are tungsten-carbide insert (TCI) bits. |
| 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. Because a mismatch stops the job, state your hole size and current connection when you inquire and we confirm the pairing on the quotation. A full bit-size to connection chart is being added to the guides; in the meantime, send your bit details on WhatsApp and we confirm the match.