Original
By certification 
Drill collars are manufactured from AISI 4145H modified steel, and are supplied in the "as rolled" surface finish condition. Alternative surface finishes are available.
Standard Size for Drill Collars | |||||||
Drill collar number and connection |
Outside Diameter |
Inside Diameter |
Length (mm) |
Bevel Diameter |
Ref. Bending Strength |
||
mm |
in |
mm |
in |
||||
NC26-35 (2 3/8 IF) |
88.9 |
3 1/2 |
38.1 |
1- 1/2 |
9150 |
82.9 |
2.42:1 |
NC31-41 (2 7/8IF) |
104.8 |
4 1/8 |
50.8 |
2 |
9150 |
100.4 |
2.43:1 |
NC46-62 (4 IF) |
158.8 |
6 1/4 |
71.4 |
2- 13/16 |
9150 or 9450 |
150.0 |
2.63:1 |
NC46-65 (4 IF) |
165.1 |
6 1/2 |
71.4 |
2- 13/16 |
9150 or 9450 |
154.8 |
3.05:1 |
NC46-67 (4 IF) |
171.4 |
6 3/4 |
57.2 |
2- 1/4 |
9150 or 9450 |
159.5 |
3.18:1 |
NC50-67 (4 1/2 IF) |
171.4 |
6 3/4 |
71.4 |
2- 13/16 |
9150 or 9450 |
159.5 |
2.37:1 |
NC50-72 (4 1/2 IF) |
184.2 |
7 1/4 |
71.4 |
2- 13/16 |
9150 or 9450 |
169.5 |
3.12:1 |
NC56-77 |
196.8 |
7 3/4 |
71.4 |
2- 13/16 |
9150 or 9450 |
185.3 |
2.70:1 |
6 5/8 REG |
209.6 |
8 1/4 |
71.4 |
2- 13/16 |
9150 or 9450 |
195.7 |
2.93:1 |
7 5/8REG |
241.3 |
9 1/2 |
76.2 |
3 |
9150 or 9450 |
223.8 |
2.81:1 |
NC70-100 |
254.0 |
10 |
76.2 |
3 |
9150 or 9450 |
237.3 |
2.81:1 |
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