Square Kelly and Hexagonal Kelly

The kelly is located at the top of the drill string and is available in square and Hexagonal forms.
In rotary table drilling, when drilling, the Kelly is matched with the square and the rotary table to transfer the ground rotary table torque to the drill pipe to drive the drill bit to rotate, and bear the weight of the drill string.In the drilling of turbine and screw, it bears the weight of the drill string and the reaction torque.
Standard:API SPEC 7-1,SY/T6509-2000
Size: Full range from 2-1/2”--6”
Material”AISI 4145H alloy steel

Specification

Normal Size(in)

Top Connection(LH)

Bottom Connection

I.D.(in)

Drive Section(in)

Standard O.D.(in)

OptionalO.D.(in)

Square O.D.(in)

Hex.O.D.(in)

Square

Hex.

A

B

2-1/2

6-5/8REG 7-3/4

4-1/2REG 5-3/4

NC26 85.7


1-1/4


3-2/7


3

6-5/8REG 7-3/4

4-1/2REG 5-3/4

NC31 4-1/8

NC26 3-3/8

1-3/4

1-1/4

4

3-3/8

3-1/2

6-5/8REG 7-3/4

4-1/2REG 5-3/4

NC384-3/4

NC31 4-1/8

2-1/4

1-3/4

4-1/2

4

4-1/4

6-5/8REG 7-3/4

4-1/2REG 5-3/4

NC384-3/4

NC38  4-3/4

2-4/5

2-1/4

5-4/7

4-4/5

6-5/8REG 7-3/4

4-1/2REG 5-3/4

NC46 6-1/4

NC38 4-3/4

2-4/5

2-1/4

5-4/7

4-4/5

5-1/4

6-5/8REG 7-3/4


NC50 6-3/8

NC46 6-1/4

3-1/4

3

7

6

6-5/8REG 7-3/4


5-1/2 FH 7

NC50 6-3/8

3-1/4

3-1/4

7

6

6

6-5/8REG 7-3/4


NC56 7

5-1/2FH 7


3-1/2


6-4/5

6-5/8REG 7-3/4



NC56 7


3-1/2


6-4/5