API-7-1 12 Mill Tooth Three Cone Bit , Oil And Gas Drill Bits 1/4" FSG127G

12 1/4" FSG127G, Steel Tooth Bit , Well Drilling Bit , Sealed Journal Bearing , TCI Tricone Bit

SIZE AVAILABLE

From 5 7/8inch to 18 1/2inch

RECOMMENDED DRILLING PARAMETERS FOR APPLICATION

Roller Cone Bit Bearings

- Functions:

   • Support radial load
   • Support thrust or axial loads
   • Secure the cone on the leg
- Supporting loads is achieved by outer and nose bearing
- Ball and friction bearings secure the cone on the leg
- Two different bearing are available: antifriction and friction
- Antifriction bearings or roller are two types: Roller-ball-roller (RBR), and roller-ball-friction
- RBR, nose roller; intermediate ball; and outer roller
- The ball secure the cone
- Size influenced by journal angle and cone size
- RBR suffers from spalling of the races of the pin
- RBR bit have short life
- Normally used with bit with diameter greater than 12.25 in with adequate space and in situation where high rotary speed is required

Application of Teeth and Tungsten Carbide Insert on Roller Cone Bit

- Length and geometry relate the rock strength
- Size of the cone and bearing structure affect the teeth
- Teeth design criteria are:
Spacing and interfitting of teeth governed by tooth strength, depth and included angle
Shape and length, dictated by formation characteristics
Types of teeth, milled or inserted
- Log slider and widely spaced teeth used for soft rock
- Long teeth allow results in breaking greater volume
- Wide spacing allows easy removal of drilled cuttings
- The included angle for soft rock from 39 to 42
- Medium hard would have a moderate number of teeth and 43 to 45 included angle
- Hard rocks need 45 to 50 included angle
- Milled teeth are faced with hardening metal to reduce wear
- Milled tooth bits are suitable for soft formation
- Insert are used for hard formation
- There are several types of insert to suit the hardness
- Chisel-shaped for soft rock
- Round or spherical for medium and hard rocks