Aperture Standard for English Threaded Nuts
|
British thread |
Round pipe threads |
Thread diameter
（inch） |
Number of teeth per inch |
Bit diameter（millimeter） |
Thread diameter（inch） |
Number of teeth per inch |
Drill diameter（millimeter） |
|
Cast iron, brass, bronze steel, malleable iron |
|
3/16
1/4
5/16
3/8
1/2
5/8
3/4
7/8
1
11/8
11/4
11/2
13/4
2 |
24
20
18
16
12
11
10
9
8
7
7
6
5
41/2 |
3.8
5.1
6.6
8
10.6
13.6
16.6
19.5
22.3
25
28.2
34
39.5
45.3 |
3.9
5.2
6.7
8.1
10.7
13.8
16.8
19.7
22.5
25.2
28.4
34.2
39.7
45.6 |
1/8
1/4
3/8
1/2
3/4
1
11/4
13/8
11/2 |
28
19
19
14
14
11
11
11
11
|
8.8
11.7
15.2
18.9
24.4
30.6
39.2
41.6
45.1 |