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BSP (G) male thread envelopes 1/8 to 1 in (ISO 228-1)
What is the outside diameter of a G1/4 BSP thread? · Hardware · basis: ISO 228-1 (G, parallel) and ISO 7-1 (R / Rc, taper) BSP major diameters and TPI
Long Earth Society build part. Pressure-tap and thermocouple ports on the LES engine heads. The engines
Exact dimensions. True size, with no printing tolerance added.
- sizes
- 6 in table
Notes
- Each file is a plain cylinder at the BSPP (G) major OD, 14 mm long, with a 0.8 mm chamfer on the end; the thread form is not modelled.
- Major OD: G1/8 9.73, G1/4 13.16, G3/8 16.66, G1/2 20.96, G3/4 26.44, G1 33.25 mm; 28, 19, 19, 14, 14 and 11 TPI.
- BSP is a 55° thread; parallel G seals on a washer or O-ring, taper R on the thread.
- BSP and NPT do not interchange: 1/2 NPT is 14 TPI 60° and 21.34 OD, G1/2 is 14 TPI 55° and 20.96 OD.
Sizes
| size | od_mm | tpi | file_length_mm |
|---|---|---|---|
| G1/8 | 9.73 | 28 | 14 |
| G1/4 | 13.16 | 19 | 14 |
| G3/8 | 16.66 | 19 | 14 |
| G1/2 | 20.96 | 14 | 14 |
| G3/4 | 26.44 | 14 | 14 |
| G1 | 33.25 | 11 | 14 |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| Wikipedia | National pipe thread | web | CC BY-SA 4.0 (text) |
| Wikipedia | British Standard Pipe | web | CC BY-SA 4.0 (text) |
| Long Earth Society | Engine builds that use these parts (videos and write-ups) | web, video | LES site |
Free files
★ Free files 6 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json
| bsp-1-8-male | G1/8 BSPP male, major OD 9.73 mm, 28 TPI, 14 mm; plain cylinder at OD | STEP · STL |
| bsp-1-4-male | G1/4 BSPP male, major OD 13.16 mm, 19 TPI, 14 mm; plain cylinder at OD | STEP · STL |
| bsp-3-8-male | G3/8 BSPP male, major OD 16.66 mm, 19 TPI, 14 mm; plain cylinder at OD | STEP · STL |
| bsp-1-2-male | G1/2 BSPP male, major OD 20.96 mm, 14 TPI, 14 mm; plain cylinder at OD | STEP · STL |
| bsp-3-4-male | G3/4 BSPP male, major OD 26.44 mm, 14 TPI, 14 mm; plain cylinder at OD | STEP · STL |
| bsp-1-male | G1 BSPP male, major OD 33.25 mm, 11 TPI, 14 mm; plain cylinder at OD | STEP · STL |
Plain text: sheet.txt · JSON: /api/geometry?object=bsp-thread-envelopes
Questions
What is the OD of G1/4?
13.16 mm, 19 TPI, 55° thread.
Are NPT and BSP interchangeable?
No: NPT is 60° and BSP 55°, the ODs differ (1/2 NPT 21.34 vs G1/2 20.96 mm) and 1/8, 1/4 and 3/8 have different TPI.