8 1/2" HA117G
(215.9mm)
l “O�?ring sealed journal bearing
Journal bearing structure with head bearing hardfaced and cone bearing silver plated to improve load capacity and anti-galling ability of the bearing. More wear and high-temperature resistant highly saturated Buna-N rubber ‘O�?ring is used to improve reliability. Larger ‘O�?ring section reduces pressure on the seal, and the boss at outer end of the seal is also helpful for reliability of the seal.
l Head OD reinforcement
Head OD are designed with carbide inserts to protect the shirttail and seal to effectively improve the bit’s ability to prevent diameter shrinkage.
l Hardfacing on shirttail
This feature can provide better protection for seal and bearing to extend the bit’s service life.
Technical specifications
IADC 1-1-7
Bearing and seal Ball and Journal bearing O-ring
Number of rows 3�?�?
Number of cutters 98
Main cutter shape / Cutter exposure Hardfaced tooth surface
Gage row cutter shape
Layout of diamond enhanced inserts /
Type of nozzle S4
Type of center nozzle YES
Shank 4 1/2 REG
Recommended makeup torque 16.3�?1.7 (KN.m)
Recommended operating parameters
WOB�?0�?190（KN�?
Ideal WOB range�?0�?50（KN�?
Rotary speed�?80 �?150 （rpm�?
Ideal Rotary speed range�?0�?20（rpm�?
The above parameters are only for reference. Optimized parameters are determined by drilling process and lithology of formations on site.
Applicable formations�?
Very soft with low compressive strength and high drillability, such as soft shale, clay and salt bed, etc.
1
4 3/4 " HA117
(120.65mm)
l “O�?ring sealed journal bearing
Journal bearing structure with head bearing hardfaced and cone bearing silver plated to improve load capacity and anti-galling ability of the bearing. More wear and high-temperature resistant highly saturated Buna-N rubber ‘O�?ring is used to improve reliability. Larger ‘O�?ring section reduces pressure on the seal, and the boss at outer end of the seal is also helpful for reliability of the seal.
l Head OD reinforcement
Head OD are designed with carbide inserts to protect the shirttail and seal to effectively improve the bit’s ability to prevent diameter shrinkage.
Technical specifications
IADC 1-1-7
Bearing and seal “O�?ring sealed journal bearing
Offset 1/8�?/DIV>
Number of rows 3�?�?
Number of cutters 74
Main cutter shape / Cutter exposure Hardfaced tooth surface
Gage row cutter shape
Layout of diamond enhanced inserts /
Type of nozzle S1
Type of center nozzle None
Shank 2 7/8 REG
Recommended makeup torque 8.1~9.5 (KN.m)
Recommended operating parameters
WOB�?35 �?105（KN�?
Ideal WOB range�?0�?0（KN�?
Rotary speed�? 120 �?60 （rpm�?
Ideal Rotary speed range�?00�?0（rpm�?
The above parameters are only for reference. Optimized parameters are determined by drilling process and lithology of formations on site.
Applicable formations
Soft to medium soft with low compressive strength or soft with harder stringers, such hard gypsolyte, soft
limestone and sandstone, etc .
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