Drill Collars

Our Drill collars for standard use are made of 4145H chromium molybdenum alloy steel. Residual elements such as sulfur and phosphorus are reduced during the steelmaking process that make the kind of material with high physical properties.

The Drill collars are available in lengths from 10 to 31 feet and outside diameter from 3-1/8" to 11". Common sizes and other relevant and important sizes are listed below.

Standard Sizes, Bores and Connections for Drill Collars

Size OD (in)
Bore ID (in)
Connection style and size
Length
(ft)
T01.±6"
Bending
strength
Radio
Approx Weight kg.
3-1/8
1-1/4
NC23
30
2.57:1
300
3-1/2
1-1/2
NC26 2-3/8IF
30
2.42:1
367
4-1/8
2
NC31 2-7/8IF
30
2.43:1
467
4-3/4
2
NC35
30
2.58:1
681
5
2-1/4
NC38 3-1/2IF
30
2.38:1
722
6
2-1/4
NC44
31
2.49:1
1169
6
2-13/16
NC44
31
2.84:1
1056
6-1/4
2-1/4
NC44
31
2.91:1
1281
6-1/4
2-13/16
NC46 41F
31
2.63:1
1160
6-1/2
2-1/4
NC46 41F
31
2.76:1
1383
6-1/2
2-13/16
NC46 41F
31
3.05:1
1277
6-3/4
2-1/4
NC46 41F
31
3.18:1
1520
7
2-1/4
NC50 4-1/2IF
31
2.54:1
1647
7
2-13/16
NC50 4-1/2IF
31
2.73:1
1548
7-1/4
2-13/16
NC50 4-1/2IF
31
3.12:1
1675
7-3/4
2-13/16
NC56 6-5/8REG
31
2.70:1
1957
8
2-13/16
NC56 6-5/8REG