DRILL DIAMETERS FOR THREAD RECOMMENDATION TABLES
CYLINDRICAL AMERICAN PIPE THREAD
NPSM |
Min Internal Diameter mm |
Max Interal Diameter mm |
Recommanded Drill Diameter mm |
1/8"-27 |
9.039 |
9.246 |
9.1 |
1/4"-18 |
11.887 |
12.217 |
12 |
3/8"-18 |
15.316 |
15.545 |
15.5 |
1/2"-14 |
18.974 |
19.279 |
19 |
3/4"-14 |
24.333 |
24.638 |
24.5 |
1"-11.1/2 |
30.506 |
30.759 |
30.5 |
1.1/4"-11.1/2 |
39.268 |
39.497 |
39.5 |
1.1/2"-11.1/2 |
45.339 |
45.568 |
45.5 |
2"-11.1/2 |
57.379 |
57.607 |
57.5 |
2.1/2"-8 |
68.783 |
69.266 |
69 |
3"-8 |
84.684 |
85.166 |
85 | |