Thread Size Chart

Click here for a guide on how to properly measure threads.

Thread Chart

Dash Size:

2

3

4

5

6

7

8

10

12

14

16

20

24

32

40

48

Tube O.D.

1/8

3/16

1/4

5/16

3/8

7/16

1/2

5/8

3/4

7/8

1

1-1/4

1-1/2

2

2-1/2

3

Hose I.D.

1/8

3/16

1/4

5/16

3/8

1/2

5/8

3/4

1

1-1/4

1-1/2

2

2-1/2

3

JIC 37° Flare Thread

5/16-24

3/8-24

7/16-20

1/2-20

9/16-18

3/4-16

7/8-14

1-1/16-12

1-3/16-12

1-5/16-12

1-5/8-12

1-7/8-12

2-1/2-12

3-12

3-1/2-12

SAE O-Ring Thread

5/16-24

3/8-24

7/16-20

1/2-20

9/16-18

3/4-16

7/8-14

1-1/16-12

1-3/16-12

1-5/16-12

1-5/8-12

1-7/8-12

2-1/2-12

NPTF Pipe Thread

1/8-27

1/4-18

3/8-18

1/2-14

3/4-14

1-11-1/2

1-1/4-11-1/2

1-1/2-11-1/2

2-11-1/2

2-1/2-8

3-8

NPSM Swivel Thread

1/8-27

1/4-18

3/8-18

1/2-14

3/4-14

1-11-1/2

1-1/4-11-1/2

1-1/2-11-1/2

2-11-1/2

Flat Face Thread

9/16-18

11/16-18

13/16-18

1-14

1-3/16-12

1-7/16-12

1-11/16-2

2-12

Code 61 Flange Head O.D.

1.19

1.335

1.50

1.75

2.00

2.38

2.81

3.31

4.00

Code 62 Flange Head O.D.

1.25

1.62

1.88

2.12

2.50

3.12

British Thread BSPP/BSPT

1/8-28

1/4-19

3/8-19

1/2-14

3/4-14

1-11

1-1/4-11

1-1/2-11

Metric Thread

10 M10x1.0

12 M12x1.5

14 M14x1.5

16 M16x1.5

18 M18x1.5

20 M20x1.5

22 M22x1.5

24 M24x1.5

26 M26x1.5

27 M27x2.0

30 M30x2.0

33 M33x2.0

36 M36x2.0

42 M42x2.0

48 M48x2.0

Copper/Nylon Air Brake Thread

7/16-24

17/32-24

11/16-20

13/16-18

1-18

SAE 45° Flare Thread

5/16-24

3/8-24

7/16-20

1/2-20

5/8-18

11/16-24

3/4-16

7/8-14

1-1/16-14

Inverted Flare Thread

5/16-28

3/8-24

7/16-24

1/2-20

5/8-18

11/16-18

3/4-18

7/8-18

1-1/16-16

Compression Thread

5/16-24

3/8-24

7/16-24

1/2-24

9/16-24

5/8-24

11/16-24

13/16-18

1-18