|
National Pipe Tapered Tap Chart
(Recommended tap drill to use for 75% thread depth)
| To Tap This Size Pipe: |
Use This Drill Bit: |
(Closest Fractional:) |
Decimal Inches: |
| 1/16-27 NPT |
Ltr.D |
- |
.2460 |
| 1/8-27 NPT |
Ltr.R |
- |
.3390 |
| 1/4-18 NPT |
7/16" |
7/16" |
.4375 |
| 3/8-18 NPT |
37/64" |
67/64" |
.5781 |
| 1/2-14 NPT |
45/64" |
45/64" |
.7031 |
| 3/4-14 NPT |
59/64" |
59/64" |
.9219 |
| 1-11 1/2 NPT |
1 5/32" |
1 5/32" |
1.1562 |
| 1 1/4-11 1/2 NPT |
1 1/2" |
1 1/2" |
1.5000 |
| 1 1/2-11 1/2 NPT |
1 47/64" |
1 47/64" |
1.7344 |
| 2-11 1/2 NPT |
2 7/32" |
2 7/32" |
2.2188 |
|