Drill collars are essential components in drilling operations, providing weight and stability to the drill string. The following table outlines key specifications for various standard drill collar models: API Boreback Box Connection API stress relieve groove pin connection Cold Rolling Thread roots Phosphate coated connections Spiral grooved or Non-Spiral (Slick Type) Type of Hardband and Hardband configuration Elevator and Slip recesses or Slip Recess only Other type of connections to meet specific needs Standard Pressed Steel Thread Protectors. Cast Steel Lifting Bail Thread Protectors upon request. Issued in accordance with API 7/7-1 and API RP7G specifications. Third Party Inspection can be performed on request at buyer’s care and expense. Silicone Molds,Resin Molds,Silicone Sphere Mold,Custom Silicone Molds Dongguan Huayuan Electronic Technology Co., Ltd , https://www.siliconefactory-oem.com
Drill Collar Connection
Drill Collar Diameter (in)
Bore Diameter (in)
Length (ft)
Linear Weight (Approx.) (lb/ft)
Displacement (Open End) (US gal/ft)
Bending Strength Ratio
NC 23-31
3-1/8
1-1/4
30
22.00
0.337
2.57:1
NC 26-35 (2-3/8 IF)
3-1/2
1-1/2
30
26.70
0.408
2.42:1
NC 31-41 (2-7/8 IF)
4-1/8
2
30 or 31
33.65
0.515
2.43:1
NC35-47
4-3/4
2
30 or 31
46.81
0.716
2.58:1
NC 38-50 (3-1/2 IF)
5
2-1/4
30 or 31
53.29
0.815
2.38:1
NC 44-60
6
2-1/4
30 or 31
82.61
1.264
2.49:1
NC 44-60
6
2-13/16
30 or 31
75.90
1.161
2.84:1
NC 44-62
6-1/4
2-1/4
30 or 31
90.52
1.385
2.91:1
NC 46 -62 (4IF)
6-1/4
2-13/16
30 or 31
83.81
1.282
2.63:1
NC 46 -65 (4IF)
6-1/2
2-1/4
30 or 31
99.52
1.522
2.76:1
NC 46-65 (4IF)
6-1/2
2-13/16
30 or 31
92.81
1.420
3.05:1
NC 46-67 (4IF)
6-3/4
2-1/4
30 or 31
108.52
1.600
3.18:1
NC 50-70 (4IF)
7
2-1/4
30 or 31
117.52
1.798
2.54:1
NC 50 -70 (4IF)
7
2-13/16
30 or 31
110.77
1.694
2.73:1
NC 50-72 (4IF)
7-1/4
2-13/16
30 or 31
119.81
1.833
3.12:1
NC 56-77
7-3/4
2-13/16
30 or 31
139.90
2.140
2.70:1
NC 56-80
8
2-13/16
30 or 31
150.81
2.307
3.02:1
6-5/8 REG
8-1/4
2-13/16
30 or 31
161.81
2.472
2.93:1
NC 61-90
9
2-13/16
30 or 31
195.81
2.995
3.17:1
7-5/8 REG
9-1/2
3
30 or 31
217.00
3.319
2.81:1
NC 70 -97
9-3/4
3
30 or 31
230.00
3.518
2.57:1
NC 70-100
10
3
30 or 31
242.97
3.717
2.81:1
8-5/8 REG
11
3
30 or 31
299.00
4.574
2.84:1
Standard Features
Options
Protection
Mill Test Certificates
Common drill collar sizes are listed in the table below. These products are manufactured according to API specifications, including API 7/7-1 and API RP7G where applicable. Customization options are available to meet specific requirements, such as additional features and proprietary connections from leading manufacturers.