Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

Whitworth Pipe Threads

BSPP (G) - British Standard Pipe Parallel and BSPT (R/Rp) – British Standard Tapered Pipe for pipes and tapered threads - G/R/Rp.

The Whitworth thread specifies a 55° thread angle and a thread depth of 0.640327p and a radius of 0.137329p where p is the pitch.

The most common types of Whitworth pipe threads are

In the UK metric ISO threads have replaced Withworth (BSW) and British Standard Fine (BSF) threads. In USA the most common threads are "Unified Fine" (UNF)  and "Unifed Coarse" (UNC).

BSPP (G) – British Standard Pipe Parallel

BSPP (G) – British Standard Pipe Parallel
Thread size
(inch)
Major Diameter
(mm)
Minor Diameter
(mm)
TPI
G 1/16 7.723 6.561 28
G 1/8 9.728 8.566 28
G 1/4 13.157 11.445 19
G 3/8 16.662 14.950 19
G 1/2 20.955 18.631 14
G 3/4 26.441 24.117 14
G 1 33.249 30.291 11
G 2 59.614 56.656 11
  • TPI = threads per inch

BSPT (R/Rp) – British Standard Tapered Pipe

BSPT (R/Rp) – British Standard Tapered Pipe
Male Thread size
(inch)
Female Thread size
(inch)
Major Diameter
(mm)
Minor Female Diameter
(mm)
TPI
R 1/16 Rp 1/16 7.723 6.490 28
R 1/8 Rp 1/8 9.728 8.495 28
R 1/4 Rp 1/4 13.157 11.341 19
R 3/8 Rp 3/8 16.662 14.846 19
R 1/2 Rp 1/2 20.955 18.489 14
R 3/4 Rp 3/4 26.441 23.975 14
R 1 Rp 1 33.249 30.111 11
R 2 Rp 2 59.614 56.476 11
  • BSPT male threads seal against threads of fixed BSPT female.
  • BSPT male and BSPP male with conical 30° seat seal against matching conical 30° seat of BSPP female swivel.
3D Engineering ToolBox - draw and model technical applications! 2D Engineering ToolBox - create and share online diagram drawing templates! Engineering ToolBox Apps - mobile online and offline engineering applications!

Unit Converter


















































6.27.14

.