螺纹代号

基本直径

内螺纹

外螺纹

大径

中径

小径

中径
公差

小径
公差

A级

B级

中径
公差

大径
公差

中径
公差

大径
公差

G1/8″×
28

9.728

9.147

8.566

+0.170
0

+0.282

0

0

-0.107

0

-0.214

0

-0.214

0

-0.214

G1/4″×
19

13.157

12.301

11.445

+0.125

+0.445

-0.125

-0.250

-0.250

0-0.250

G3/8″×
19

16.662

15.806

14.950

+0.125

0

+0.445

0

0

-0.125

0

-0.250

0

-0.250

0

-0.250

G1/2″×
14

20.955

19.793

18.631

+0.142

0

+0.541

0

0

-0.142

0

-0.284

0

-0.284

0

-0.284

G5/8″×
14

22.911

21.749

20.587

+0.142

0

+0.541

0

0

-0.142

0

-0.284

0

-0.284

0

-0.284

G3/4″×
14

26.441

25.279

24.117

+0.142

0

+0.541

0

0

-0.142

0

-0.284

0

-0.284

0

-0.284

G1″×11

33.249

31.770

30.291

+0.180

0

+0.640

0

0

-0.180

0

-0.360

0

-0.360

0

-0.360

G1.1/4″×11

41.910

40.431

38.952

+0.180

0

+0.640

0

0

-0.180

0

-0.360

0

-0.360

0

-0.360

G1.1/2″
×11

47.803

46.324

44.854

+0.180

0

+0.640

0

0

-0.180

0

-0.360

0

-0.360

0

-0.360

G2″×11

59.614

58.135

56.656

+0.180

0

+0.640

0

0

-0.180

0

-0.360

0

-0.360

0

-0.360

G2.1/2”X
11

75.184

73.705

72.226

+0.217

0

+0.640

0

0

-0.217

0

-0.434

0

-0.434

0

-0.434

G3”X11

87.884

86.405

84.926

+0.217

0

+0.640

0

0

-0.217

0

-0.434

0

-0.434

0

-0.434

G3.1/2”X
11

100.330

98.851

97.372

+0.217

0

+0.640

0

0

-0.217

0

-0.434

0

-0.434

0

-0.434

螺纹代号

基面上的直径

基准长度

有效螺纹长度

圆锥
内螺
纹基
面轴
向位
移偏
差（
±mm）

大径

中径

小径

基本

最大

最小

基本

最大

最小

R1/8″×28

9.728

9.147

8.566

4.0

4.9

3.1

6.5

7.4

5.6

1.1

R1/4″×19

13.157

12.301

11.445

6.0

7.3

4.7

9.7

11.0

8.4

1.7

R3/8″×19

16.662

15.806

14.950

6.4

7.7

5.1

10.1

11.4

8.8

1.7

R1/2″×14

20.955

19.793

18.631

8.2

10.0

6.4

13.2

15.0

11.4

2.3

R3/4″×14

26.441

25.279

24.117

9.5

11.3

7.7

14.5

16.3

12.7

2.3

R1″×11

33.249

31.770

30.291

10.4

12.7

8.1

16.8

19.1

14.5

2.9

R1.1/4″×11

41.910

40.431

38.952

12.7

15.0

10.4

19.1

21.4

16.8

2.9

R1.1/2″×11

47.803

46.324

44.845

12.7

15.0

10.4

19.1

21.4

16.8

2.9

R2″×11

59.614

58.135

56.656

15.9

18.2

13.6

23.4

25.7

21.1

2.9

R2.1/2”X11

75.184

73.705

72.226

17.5

21.0

14.0

26.7

30.2

23.2

3.5

R3”X11

87.884

86.405

84.926

20.6

24.1

17.1

29.8

33.3

26.3

3.5

R3.1/2”X11

100.330

98.851

97.372

22.2

25.7

18.7

31.4

34.9

27.9

3.5

螺纹代号

基本尺寸

英寸

大径mm
d=D

螺距mm

p

每英寸牙数
tpi

中径mm
d2=D2

小径
外螺纹
d3

牙型高度
H1

圆弧尺寸
r

底孔尺寸
mm

R 1/16

1/16"

7.723

0.907

28

7.142

6.561

0.581

0.125

6.4

R 1/8

1/8"

9.728

0.907

28

9.147

8.566

0.581

0.125

8.4

R 1/4

1/4"

13.157

1.337

19

12.301

11.445

0.856

0.184

11.2

R 3/8

3/8"

16.662

1.337

19

15.806

14.950

0.856

0.184

14.75

R 1/2

1/2"

20.955

1.814

14

19.793

18.631

1.162

0.249

18.25

R 3/4

3/4"

26.441

1.814

14

25.279

24.117

1.162

0.249

23.75

R 1

1"

33.249

2.309

11

31.77

30.291

1.479

0.317

30

R 1 1/4

1 1/4"

41.910

2.309

11

40.431

38.952

1.479

0.317

38.5

R 1 1/2

1 1/2"

47.803

2.309

11

46.324

44.845

1.479

0.317

44.5

R 2

2"

59.614

2.309

11

58.135

56.656

1.479

0.317

56

R 2 1/2

2 1/2"

75.184

2.309

11

73.705

72.226

1.479

0.317

71

R 3

3"

87.884

2.309

11

86.405

84.926

1.479

0.317

85.5

R 4

4"

113.030

2.309

11

111.551

110.072

1.479

0.317

110.5

R 5

5"

138.430

2.309

11

136.951

135.472

1.479

0.317

136

R 6

6"

163.830

2.309

11

162.351

160.872

1.479

0.317

161.5