BA screw sizes
by Russ Elliott
|
BA no. |
tpi (threads per inch) |
Tapping drill size (mm) |
Clearance drill size (mm) |
0 |
25.40 |
5.2 |
6.1 |
1 |
28.22 |
4.5 |
5.4 |
2 |
31.35 |
4.1 |
4.8 |
3 |
34.79 |
3.5 |
4.2 |
4 |
38.48 |
3.0 |
3.7 |
5 |
43.05 |
2.65 |
3.3 |
6 |
47.92 |
2.3 |
2.85 |
7 |
52.91 |
2.1 |
2.55 |
8 |
59.07 |
1.8 |
2.3 |
9 |
65.12 |
1.6 |
1.95 |
10 |
72.57 |
1.4 |
1.75 |
11 |
81.93 |
1.2 |
1.5 |
12 |
90.71 |
1.05 |
1.3 |
13 |
101.60 |
0.975 |
1.15 |
14 |
110.43 |
0.80 |
1.00 |
15 |
120.95 |
0.70 |
0.90 |
16 |
133.68 |
0.60 |
0.80 |
|