BRITISH STANDARD WHITWORTH FORM THREADS (55o angle)
DIA.
BSW
BSF
BSB
BSP & BSPT
ME/WHITFORM
BSCon
Sizes
TPI
Drill
TPI
Drill
TPI
Drill
TPI
Drill
TPI
Drill
TPI
Drill
1/16
60
1.2
3/32
48
1.9
1/8
40
2.55
28
8.8
40
2.55
5/32
32
3.2
40
3.3
3/16
24
3.7
32
4.0
32, 40
4.0, 4.0
7/32
24
4.5
28
4.6
40
4.8
1/4
20
5.1
26
5.3
26
5.3
19
11.8
24,28,32,40
5.3,5.4,5.5,5.5
9/32
20
5.8
26
6.0
26
5.8
32
6.1
5/16
18
6.5
22
6.8
26
5.8
24, 32, 40
6.75, 7.0, 7.3
3/8
16
7.9
20
8.3
26
8.4
19
15.25
24, 32, 40
8.4, 8.6, 8.9
7/16
14
9.3
18
9.7
26
10.0
20,24,32,40
9.8,10,10.3,10.5
1/2
12
10.5
16
11.1
26
11.5
14
19.0
20,24,32,40
11.5,11.9,11.9,12
18
11.5
9/16
12
12.1
16
12.7
26
13.1
20
13.1
5/8
11
13.5
14
14
26
14.7
14
21.0
20
14.5
18
14.2
11/16
11
15.1
14
15.5
26
16.5
20
16.2
3/4
10
16.25
12
16.75
26
17.8
14
24.5
14, 20
17.1, 17.8
16
17.5
7/8
9
19.25
11
19.75
26
21.0
14
28.25
14,16, 20
20.2, 20.6, 21.0
16
20.6
15/16
9
20.6
11
21.5
1
8
22.0
10
22.75
26
24.2
11
30.75
12, 20
23.0, 24.0
16
23.8
1.1/8
7
24.75
9
25.5
26
27.5
1.1/4
7
28.0
9
28.5
26
30.5
11
39.5
16
30.1
1.3/8
6
30.1
8
31.5
26
33.7
1.1/2
6
33.5
8
34.5
26
36.9
11
45.00
14
36.1
1.5/8
5
35.7
8
37.7
26
40.0
1.3/4
5
39
7
41.0
26
43.5
11
51.0
1.7/8
4.1/2
41.3
7
43.7
26
46.5
2
4.1/2
44.5
7
47.0
26
49.6
11
57.0