|
Recommended tapping and clearance drill sizes
 |
| BSF British Standard Fine Thread |
| d1 Inch |
TPI |
d2 mm |
d3 mm |
|
d1 Inch |
TPI |
d2 mm |
d3 mm |
| 3/16 |
32 |
4.00 |
4.90 |
|
11/16 |
14/td>
| 15.50 |
17.75 |
| 7/32 |
28 |
4.60 |
5.70 |
|
3/4 |
12 |
16.75 |
19.25 |
| 1/4 |
26 |
5.30 |
6.50 |
|
7/8 |
11 |
19.75 |
22.50 |
| 9/32 |
26 |
6.10 |
7.30 |
|
1 |
10 |
22.75 |
25.75 |
| 5/16 |
22 |
6.80 |
8.10 |
|
1 1/8 |
9 |
25.50 |
29.00 |
| 3/8 |
20 |
8.30 |
9.70 |
|
1 1/4 |
9 |
28.50 |
32.00 |
| 7/16 |
18 |
9.70 |
11.30 |
|
1 3/8 |
8 |
31.50 |
35.50 |
| 1/2 |
16 |
11.10 |
13.00 |
|
1 1/2 |
8 |
34.50 |
38.50 |
| 9/16 |
16 |
12.70 |
14.50 |
|
1 3/4 |
7 |
40.50 |
50.00 |
| 5/8 |
14 |
14.00 |
16.25 |
|
2 |
7 |
47.00 |
50.50 |
The above information is for guidence only and should not be used when working to stringent specifications.
|
