Pipe Tap Drill Sizes
| TAP SIZE |
*NPT |
*NPFT |
STRAIGHT |
| TAP DRILL |
DECIMAL EQUIV. |
TAP DRILL |
DECIMAL EQUIV. |
TAP DRILL |
DECIMAL EQUIV. |
| 1/16 |
D |
0.246 |
D |
0.246 |
1/4 |
0.25 |
| 1/8 |
Q |
0.332 |
R |
0.339 |
11/32 |
0.3438 |
| 1/4 |
7/16 |
0.4375 |
7/16 |
0.4375 |
7/16 |
0.4375 |
| 3/8 |
9/16 |
0.5625 |
37/64 |
0.5781 |
37/64 |
0.5781 |
| 1/2 |
45/64 |
0.7031 |
45/64 |
0.7031 |
23/32 |
0.7188 |
| 3/4 |
29/32 |
0.9062 |
59/64 |
0.9219 |
59/64 |
0.9219 |
| 1 |
1 9/64 |
1.1406 |
1 5/32 |
1.1562 |
1 5/32 |
1.1562 |
| 1 1/4 |
1 31/64 |
1.4844 |
1 1/2 |
1.5 |
1 1/2 |
1.5 |
| 1 1/2 |
1 47/64 |
1.7344 |
1 47/64 |
1.7344 |
1 3/4 |
1.75 |
| 2 |
2 13/64 |
2.2031 |
2 7/32 |
2.2188 |
2 7/32 |
2.2188 |
| 2 1/2 |
2 5/8 |
2.625 |
2 41/64 |
2.6406 |
2 21/32 |
2.6562 |
| 3 |
|
|
3 17/64 |
3.2656 |
|
|
* For tapping without reaming.