Size(inch)

STD

Upper box connection

Lower pin connection

I.D..

Driving Section

mm

Inch

Connection(LH)

O.D.

Connection(LH)

O.D.

Cross flat

For square kelly

Cross corner for hexakelly

STD

Optional

STD

Optional

63.5

2 1/2

12.19

6 5/8REG

4 1/2 REG

196.8

146.0

NC26

85.7

31.8

63.5

83.3

76.2

3

12.19

6 5/8REG

4 1/2 REG

196.8

146.0

NC31

104.8

44.4

76.2

100.0

85.7

88.9

3 1/2

12.19

6 5/8REG

4 1/2 REG

196.8

146.0

NC38

120.6

57.2

88.9

115.1

100.8

108.0

4 1/4

12.9

6 5/8REG

196.8

146.0

NC46

158.8

71.4

108.0

141.3

122.2

6 5/8REG

196.8

146.0

NC50

161.9

71.4

108.0

141.3

122.2

133.4

5 1/4

12.9

6 5/8REG

196.8

5 1/2 FH

177.8

82.6

133.3

175.4

151.6

6 5/8REG

196.8

NC56

177.8

82.6

133.3

175.4

151.6