We supply slick drill collars, spiral drill collars and non-magnetic drill collars; their sizes are from 3-1/8 to 11
inches. Besides the drill collars in the table below, we can supply other drill collars at customers' request.
Materials:
Drill collars are manufactured from AISI 4145H modified steel, and are supplied in the "as rolled" surface finish condition. Alternative surface finishes are available.
Rigid Inspection Procedures:
We inspect all our drill collars to ensure compliance with API SPEC 7-1 standards. These inspections include visual dimensional checks as well as ultrasonic inspections over the entire body of
the drill collar.
Cold Rolling:
Drill collar thread roots, as well as elevator recess upper radius, are cold-rolled. Cold rolling creates a compressive recess upper radius stress condition that increases fatigue life by
minimizing crack initiation.
Phosphate-coated or Copper Plating:
All connections are phosphate-coated or copper plated to improve resistance to corrosion.
Slip Groove, Elevator Groove and Size:
Lake offers optional slip and elevator recesses to improve handling efficiency and safety. Unless otherwise specified, slip and elevator recesses are machined in compliance with API spec 7-1
guidelines.
Thread Protectors:
Our company offers steel, cast steel and plastic steel thread protectors for its drill stem products.
Nominal size
|
D
|
|
d
|
|
L
|
DF(mm)
|
Bending Strength
|
ratio
|
|
mm
|
In
|
mm
|
in
|
mm
|
|
|
NC31-41(2-7/8IF)
|
104.8
|
37994
|
50.8
|
2
|
9150
|
100.4
|
2.43:1
|
NC35-47
|
120.7
|
38050
|
50.8
|
2
|
9150
|
114.7
|
2.58:1
|
NC38-50(3-1/2IF)
|
127
|
5
|
57.2
|
37260
|
9150
|
121
|
2.38:1
|
↓
|
↓
|
↓
|
↓
|
↓
|
↓
|
↓
|
↓
|
7-5/8REG
|
241.3
|
39815
|
76.2
|
3
|
9150/9450
|
223.8
|
2.81:1
|
NC70-97
|
247.6
|
39876
|
76.2
|
3
|
9150/9450
|
232.6
|
2.57:1
|
NC70-100
|
254
|
10
|
76.2
|
3
|
9150/9450
|
237.3
|
2.81:1
|