1/16 NPT tap drill size
Letter D
- Inches
- 0.2460
- Millimetres
- 6.25
- Threads per inch
- 27
Drill a Letter D hole, then cut the 1/16 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.
Some charts list Letter C (0.242 in) for 1/16 NPT.
1/16 NPT thread and hole sizes
| Thread | 1/16 NPT National Pipe Taper, 27 threads per inch |
|---|---|
| Tap drill, no reamer | Letter D 0.2460 in, 6.25 mm |
| Pitch | 0.0370 in 0.941 mm |
Tools for this job
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