BSPT (R) — British tapered pipe

1-11 BSPT

1-11 BSPT pipe thread: 11 TPI, major Ø 33.249 mm.

Tap-drill calculator Identify a thread

Tap drill

30 mm

33.249 mm major Ø

Profile

Thread form & key diameters

Dimensions

Designation	1-11 BSPT
Major (outside) diameter	33.249 mm · 1.309"
Pitch	2.309 mm · 11 TPI
Pitch diameter	31.749 mm · 1.25"
Minor diameter (external)	30.416 mm · 1.1975"
Minor diameter (internal)	30.749 mm · 1.2106"
Recommended tap drill	30 mm

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

1-11 BSPT is a BSPT pipe thread running at 11 threads per inch on a 33.249 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.

Same diameter

Other 1" BSPT threads

1-11 BSPPTap —Ø 33.249 mm · pitch 2.309 mm

Nearby sizes

More bspt (r) — british tapered pipe threads

3/4-14 BSPTTap 23.75 mmØ 26.441 mm · pitch 1.814 mm 1-1/4-11 BSPTTap 38.75 mmØ 41.91 mm · pitch 2.309 mm 1/2-14 BSPTTap 18.25 mmØ 20.955 mm · pitch 1.814 mm 1-1/2-11 BSPTTap 44.5 mmØ 47.803 mm · pitch 2.309 mm 3/8-19 BSPTTap 14.75 mmØ 16.662 mm · pitch 1.337 mm 1/4-19 BSPTTap 11.2 mmØ 13.157 mm · pitch 1.337 mm 1/8-28 BSPTTap 8.4 mmØ 9.728 mm · pitch 0.907 mm 2-11 BSPTTap 56.5 mmØ 59.614 mm · pitch 2.309 mm