Roller cone bit 250.8 712Y (9 ⅞" 712) (152 mm thread)

The bit is designed for drilling of hard abrasive rock formations, e.g. granite-porphyry, silicized limestone, magnetite and hematite-magnetite hard ore, ferrous, monolithic and thick quartzite, medium-grained diorite, thick garnet skarn, quartzeous gneiss, diabase and basalt, emery chlorite ore, weak pegmatite and quartzeous magnesite, most frequently found in gold, iron and granite mines.
Recommended drilling parameters for maximum efficiency of the bit: low and medium rotation speed (60-115 RPM) and axial load from 120 to 230 kN.
Rock strength range - from 38 000 to 60 000 PSI.

1 / 6


Bit diameter, mm 250.8
Bit diameter, inch 9 ⅞
Bit designation, IADC 712Y
Connection thread, API 6 ⅝" REG
Bearing type Air-cooled, on rolling bearings
Formation type For hard abrasive formations
Rotation speed. RPM 115-60
Max. applicable load, kN 120-230
Weight, kg 57.7
Bearing/cooling type Roller – Ball – Roller / Air cooling
Blow-through type Side / center
Cutting structure Tungsten carbide inserts