3/8 NPT tap drill size
37/64"
- Inches
- 0.5781
- Millimetres
- 14.68
- Threads per inch
- 18
Drill a 37/64" hole, then cut the 3/8 NPT thread with a taper pipe tap. This is the size for drilling and tapping with no reamer step.
Charts differ on pipe threads. Some list a smaller drill because they assume the hole is taper-reamed first. If you ream, use the drill size your tap or reamer maker lists.
3/8 NPT thread and hole sizes
| Thread | 3/8 NPT National Pipe Taper, 18 threads per inch |
|---|---|
| Tap drill, no reamer | 37/64" 0.5781 in, 14.68 mm |
| Pitch | 0.0556 in 1.411 mm |
Tools for this job
As an Amazon Associate we earn from qualifying purchases. Details