For very soft formations:
Very soft, poorly compacted rockssuch as shale clays, clays, poorly compacted clays and sandstones,limestones, salts, gypsum, hard coals, iron ores. These surfaces have low compressive strength
High penetration rates are ensured by a considerable offset of cone axis against the centre line of the bit and long sharp teeth. The teeth are reinforced with hard metal ensuring appropriate durability. The tooth spacing & the offset ensures increased penetration rates and efficient bore-hole cleaning for very soft and viscous formations.
For Soft Formations:
Soft and medium-compacted rocks such as: lime clays, sandstones with lime binder, conglomerates, porous gypsum, soft anhydrites, marbles with clay-silica etc
Long teeth with low top angle and considerable cone axis offset against the centre line of the bit ensure high penetration rates. The teeth are reinforced with hard metal and gauge rows are additionally reinforced for better gauge protection.
For Medium Formation:
Medium-hard and abrasive rocks such as: sandstones interspersed with streaks of quartz, hard limestone, conglomerates with limestone, or silica binder, crystalline dolomites, hematite ores, etc.
The teeth of outer rows have properly increased hardfaced gage surface. The teeth spaced closely. Additionally, the bit is gage protected by means of inserts which ensures its high durability.
For Hard formations:
Hard abrasive rocks such as: sandstones with quartz binder, hard quartz shales,granites,and metamorphic rocks etc.
Short teeth with great top angle, closely spaced. The spacing of tooth are closer. The teeth of outer rows have increased gage surface and are additionally reinforced with inserts to ensure durability and sufficient gage protection.