1/2 NPT Tap Drill Size and Pipe Thread Bit
Use a 23/32 drill bit
1/2-14 NPT · 0.7188 in / 18.26 mm · pipe taper
1/2 NPT is a larger tapered pipe thread. The drill is 23/32 in, sized to the pipe taper for a clean tap.
At a glance
| Tap drill | 23/32 |
|---|---|
| Inches | 0.7188 in |
| Millimetres | 18.26 mm |
| Threads per inch | 14 |
Why this size
NPT is a taper pipe thread. The drill is sized to the pipe minor diameter at the gauge plane. Tap drill: 23/32 (0.7188 in / 18.26 mm).
NPT threads taper so the drill is not set by percent engagement. 23/32 in is the correct 1/2 NPT tap drill.
Related sizes
Compare with adjacent threads – coarse, fine and the opposite measurement system: