Standard Size for Drill Collars

Drill collar number and connection

Outside Diameter

Inside Diameter

Length

mm

Bevel Diameter

Ref. Bending strength
ratio

mm

in

mm

in

NC23 – 31

79.4

3 1/8

31.8

1- 1/4

9150

76.2

2.57:1

NC35-7

120.7

4 3/4

50.8

2

9150

114.7

2.58:1

NC44-60

152.4

6

57.2

2- 1/4

9150 or 9450

144.5

2.49:1

NC44-60

152.4

6

71.4

2- 13/16

9150 or 9450

144.5

2.84:1

NC44-62

158.8

6 1/4

57.2

2- 1/4

9150 or 9450

149.2

2.91:1

NC46-65(4 IF)

165.1

6 1/2

57.2

2- 1/4

9150 or 9450

154.8

2.76:1

NC56-80

203.2

8

71.4

2- 13/16

9150 or 9450

190.1

3.02:1

6 5/8REG

209.6

8 1/4

71.4

2- 13/16

9150 or 9450

195.7

2.93:1

NC70-97

247.6

9 3/4

76.2

3

9150 or 9450

232.6

2.57:1

8 5/8REG

279.4

11

76.2

3

9150 or 9450

266.7

2.84:1