The roller kelly bushing is the main tool allocated for drilling equipments, and available with different specifi cations according to different kelly sizes,there are also different types in each specifi cation : which are light and heavy type . The roller kelly bushing has two driving methods:four-pin driving and four-direction driving.
Technical parameters and specifi cations
| Kelly size |
Four-pin driving |
Four-direction driving |
| in |
mm |
Center distance(mm) |
Diameter (mm) |
Across side(mm) |
| 3 1/2 |
88.9 |
654.05 |
82.9 |
332or342 |
| 4 1/2 |
107.95 |
| 5 1/2 |
133.35 | |
