DRILL DIAMETERS FOR THREAD RECOMMENDATION TABLES
TAPERED WITHWORTH PIPE THREAD
Tap Rc |
Number of t.p.i. |
Drill Diameter mm |
Ex1 |
1/8 |
28 |
8.8 |
0 |
1/4 |
19 |
11.2 |
0 |
3/8 |
19 |
14.75 |
0 |
1/2 |
14 |
18.25 |
0 |
5/8 |
14 |
20.25 |
0 |
3/4 |
14 |
23.75 |
0 |
7/8 |
14 |
27.5 |
0 |
1 |
11 |
30 |
0 |
1.1/8 |
11 |
34.5 |
0 |
1.1/4 |
11 |
38.5 |
0 |
1.3/8 |
11 |
41 |
0 |
1.1/2 |
11 |
44.5 |
0 |
1.3/4 |
11 |
50 |
0 |
2 |
11 |
56 |
0 |
2.1/4 |
11 |
62 |
0 |
2.1/2 |
11 |
71.5 |
0 |
2.3/4 |
11 |
78 |
0 |
3 |
11 |
84 |
0 | |