BSPT (R) - British tapered pipe

1/2-14 BSPT

1/2-14 BSPT pipe thread: 14 TPI, major Ø 20.955 mm.

Tap drill
18.25 mm
20.955 mm major Ø

Profile

Thread form & key diameters

Major Ø 20.955 mmP 1.814 mm55°Root Ø 18.729 mm · Pitch Ø 19.777 mm1/2-14 BSPT14 TPI · 55° form

Dimensions

Dimensions, drill sizes and wrench sizes for 1/2-14 BSPT.
Designation1/2-14 BSPT
Major (outside) diameter20.955 mm · 0.825"
Pitch1.814 mm · 14 TPI
Pitch diameter19.777 mm · 0.7786"
Minor diameter (external)18.729 mm · 0.7374"
Minor diameter (internal)18.991 mm · 0.7477"
Recommended tap drill18.25 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 1/2-14 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 1/2-14 BSPT?

1/2-14 BSPT is a BSPT pipe thread running at 14 threads per inch on a 20.955 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 1/2-14 BSPT?

Drill 18.25 mm before tapping 1/2-14 BSPT. BSPT (R) is a 55° Whitworth tapered thread that seals on the flanks.

Is 1/2-14 BSPT a tapered or parallel thread?

1/2-14 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 1/2-14 BSPT have?

1/2-14 BSPT runs at 14 threads per inch, a pitch of 1.814 mm, on a major diameter of 20.955 mm.

Is there a torque spec for 1/2-14 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 1/2" BSPT threads

The pipe this thread runs on

NPS 1/2 pipe

NPS 1/2 pipe is 0.84 in across the outside whatever the schedule; at standard wall (std) the wall is 0.109 in and the bore 0.622 in.

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

Nearby sizes

More bspt (r) - british tapered pipe threads