NPT - American tapered pipe
1/8-27 NPT pipe thread: 27 TPI, major Ø 10.29 mm.
Profile
| Designation | 1/8-27 NPT |
|---|---|
| Major (outside) diameter | 10.29 mm · 0.4051" |
| Pitch | 0.941 mm · 27 TPI |
| Pitch diameter | 9.679 mm · 0.3811" |
| Minor diameter (external) | 9.136 mm · 0.3597" |
| Minor diameter (internal) | 9.272 mm · 0.365" |
| Recommended tap drill | 8.74 mm |
Pipe threads are made up to a seal against the mating flanks, not tightened to a bolt preload, so no proof load or tightening-torque figure applies.
The bolt schedule collects the fasteners for one job onto a single sheet - tap drill, wrench size, grade and tightening torque on every line, taken straight from pages like this one. Free schedules hold 3 lines and are saved in this browser only.
1/8-27 NPT is a NPT pipe thread running at 27 threads per inch on a 10.29 mm major diameter. NPT is a 60° tapered thread that seals on the flanks; use a tapered reamer after drilling for a full-form thread.
All values are generated from the standard thread formulas (ISO 68-1 / ASME B1.1) and published standard tables - not hand-entered. See the full reference.
Drill 8.74 mm before tapping 1/8-27 NPT. NPT is a 60° tapered thread that seals on the flanks; use a tapered reamer after drilling for a full-form thread.
1/8-27 NPT is tapered. NPT is a 60° tapered thread that seals as the flanks wedge together, normally with thread sealant or PTFE tape.
1/8-27 NPT runs at 27 threads per inch, a pitch of 0.941 mm, on a major diameter of 10.29 mm.
No. Pipe threads are made up to a seal against the mating flanks, not tightened to a bolt preload, so no proof load or tightening-torque figure applies.
The pipe this thread runs on
NPS 1/8 pipe is 0.405 in across the outside whatever the schedule; at standard wall (std) the wall is 0.068 in and the bore 0.269 in.
Full dimensions for the standard wall · every schedule in the chart
Nearby sizes