BSPT (R) - British tapered pipe

1-1/2-11 BSPT

1-1/2-11 BSPT pipe thread: 11 TPI, major Ø 47.803 mm.

Tap drill
44.5 mm
47.803 mm major Ø

Profile

Thread form & key diameters

Major Ø 47.803 mmP 2.309 mm55°Root Ø 44.97 mm · Pitch Ø 46.303 mm1-1/2-11 BSPT11 TPI · 55° form

Dimensions

Dimensions, drill sizes and wrench sizes for 1-1/2-11 BSPT.
Designation1-1/2-11 BSPT
Major (outside) diameter47.803 mm · 1.882"
Pitch2.309 mm · 11 TPI
Pitch diameter46.303 mm · 1.823"
Minor diameter (external)44.97 mm · 1.7705"
Minor diameter (internal)45.303 mm · 1.7836"
Recommended tap drill44.5 mm

Tightening torque estimate

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.

Put 1-1/2-11 BSPT on a job sheet

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.

Open bolt schedule

What tap drill do I need for 1-1/2-11 BSPT?

1-1/2-11 BSPT is a BSPT pipe thread running at 11 threads per inch on a 47.803 mm major diameter. BSPT (R) is a 55° Whitworth tapered thread that seals on the flanks.

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.

Frequently asked questions

What drill size do I need to tap 1-1/2-11 BSPT?

Drill 44.5 mm before tapping 1-1/2-11 BSPT. BSPT (R) is a 55° Whitworth tapered thread that seals on the flanks.

Is 1-1/2-11 BSPT a tapered or parallel thread?

1-1/2-11 BSPT is tapered. BSPT (R) is a 55° Whitworth tapered thread that seals as the flanks wedge together, normally with thread sealant or PTFE tape.

How many threads per inch does 1-1/2-11 BSPT have?

1-1/2-11 BSPT runs at 11 threads per inch, a pitch of 2.309 mm, on a major diameter of 47.803 mm.

Is there a torque spec for 1-1/2-11 BSPT?

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.

Same diameter

Other 1-1/2" BSPT threads

The pipe this thread runs on

NPS 1-1/2 pipe

NPS 1-1/2 pipe is 1.9 in across the outside whatever the schedule; at standard wall (std) the wall is 0.145 in and the bore 1.61 in.

Full dimensions for the standard wall · every schedule in the chart

Nearby sizes

More bspt (r) - british tapered pipe threads