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Technical Specifications

 

8 1/2 RS3

 Diameter: 215.9mm (8 1/2")  
IADC Code: 135  
Design number: UT286  
State standard designation: МС-ЦГВУ  
 

Specification
Gradient angle of axle journal 33°
Axle journal offset relative to drill bit axis 4.80 mm
Bearing type Roller bearing
Sealing Elastomer
Total number of inserts (inner/heel row) 85 (42/43)
Total number of insert rows (inner/heel row) 8 (5/3)
Number of changeable nozzles 4
Connecting thread З-117 (4 1/2 REG)
Drill bit net weight, kg 34.00
Drill bit gross weight, kg 35.00
 

Recommended Drilling Conditions
Rotation speed 300-40 rpm
Thrust load 7.00-8.00 t (15400 - 17600 lbs)
The lower level of rotation speed value corresponds the upper level of thrust load value and vice versa.
 

Purpose
The drill bit is designed for drilling soft formations with medium hard streaks
 

Design Features
Combined circulation (central and side) for what the screw from the central unit must be unscrewed.

The shirttail and leg entering edge are hardfaced with tungsten carbide

The leg is protected with tungsten carbide inserts

2 rows of carbide inserts on the reverse cone of the cones.
 

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