NPT - American tapered pipe
1-1/4-11.5 NPT pipe thread: 11.5 TPI, major Ø 42.16 mm.
Profile
| Designation | 1-1/4-11.5 NPT |
|---|---|
| Major (outside) diameter | 42.16 mm · 1.6598" |
| Pitch | 2.209 mm · 11.5 TPI |
| Pitch diameter | 40.725 mm · 1.6034" |
| Minor diameter (external) | 39.45 mm · 1.5532" |
| Minor diameter (internal) | 39.769 mm · 1.5657" |
| Recommended tap drill | 38.1 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.
1-1/4-11.5 NPT is a NPT pipe thread running at 11.5 threads per inch on a 42.16 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 38.1 mm before tapping 1-1/4-11.5 NPT. NPT is a 60° tapered thread that seals on the flanks; use a tapered reamer after drilling for a full-form thread.
1-1/4-11.5 NPT is tapered. NPT is a 60° tapered thread that seals as the flanks wedge together, normally with thread sealant or PTFE tape.
1-1/4-11.5 NPT runs at 11.5 threads per inch, a pitch of 2.209 mm, on a major diameter of 42.16 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 1-1/4 pipe is 1.66 in across the outside whatever the schedule; at standard wall (std) the wall is 0.14 in and the bore 1.38 in.
Full dimensions for the standard wall · every schedule in the chart
Nearby sizes