BSP taper pipe threads R and Rp (ISO 7-1), 1/16 to 6: TPI, pitch, gauge-plane diameter, gauge length + 8 male taper STEP/STL files — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/bsp-taper-pipe-threads-r-rp-iso-7-1/ (sheet CC BY 4.0) Basis: ISO 7-1 sample Table 1 (d, d2, d1, pitch) with gauge length from Engineering ToolBox and Wikipedia; EN 10255 tube sizes for the example stubs; McMaster-Carr pipe fittings linked Catalog version: 2026-10-20 Sizes: see table below - R is the external taper pipe thread (taper 1:16 on diameter), Rp the internal PARALLEL thread and Rc the internal taper thread (ISO 7-1 designations). The diameters above are at the gauge plane; the thread gets 1 mm smaller in diameter for every 16 mm toward the end. The gauge length a is the distance from the gauge plane to the small end of the external thread. - Numbers: ISO 7-1 sample Table 1 (iTeh) for the pitch, d, d2 and d1 of all 15 sizes (the generator re-checks P = 25.4 / TPI, d2 = d - 0.640327 P and d1 = d - 1.280654 P on every row); gauge length a from Engineering ToolBox's ISO 7-1 table and the Wikipedia British Standard Pipe table, which agree on 1/8, 1/2 and 1. R 4 and R 5 gauge lengths (25.4, 28.6) come from Engineering ToolBox only and R 6 (28.6) from Wikipedia only: the iTeh scan's gauge-length column was not legible, so there is no second source for those three. The tolerance on gauge length, the useful thread length and the fitting allowance were not readable in the sample and are left out. - Files: 8 male taper envelopes for R 1-1/4 to R 6. Each is a cone from the free end to the gauge plane (major Ø d at the gauge plane, Ø d - a/16 at the free end) joined to an EXAMPLE EN 10255 medium tube stub (30 mm long, our example length, OD and wall below). The stub OD is larger than d on every size, as in a real threaded tube. Sizes up to R 1 (and BSP 1/8 to 1 as plain male ends) are on the 'Pipe thread envelopes' page. - EN 10255 medium tube used for the stub (OD x wall, mm): 1-1/4 = 42.4 x 3.25, 1-1/2 = 48.3 x 3.25, 2 = 60.3 x 3.65, 2-1/2 = 76.1 x 3.65, 3 = 88.9 x 4.05, 4 = 114.3 x 4.5, 5 = 139.7 x 4.85, 6 = 165.1 x 4.85. BS 1387 tables (Engineering ToolBox) give a slightly different OD for the same nominal bores (medium / heavy OD 42.9, 48.8, 60.8, 76.6, 89.5, 114.9, 140.6, 165.1) and walls (3.2, 3.2, 3.6, 3.6, 4.0, 4.5, 5.0, 5.0): the two standards differ, so the stub is an example, not a fixed size. - Left out: Rc internal taper details, the Rp internal tolerances, NPT (ASME B1.20.1 has its own page), JIS PT, and BSPT in tapped-hole drill sizes. size TPI pitch P, mm major Ø d at gauge plane, mm pitch Ø d2, mm minor Ø d1, mm gauge length a, mm free-end major Ø (d - a/16), mm source R / Rp 1/16 28 0.907 7.723 7.142 6.561 4 7.473 ISO 7-1 sample + ETB R / Rp 1/8 28 0.907 9.728 9.147 8.566 4 9.478 ISO 7-1 sample + ETB/Wikipedia R / Rp 1/4 19 1.337 13.157 12.301 11.445 6 12.782 ISO 7-1 sample + ETB/Wikipedia R / Rp 3/8 19 1.337 16.662 15.806 14.95 6.4 16.262 ISO 7-1 sample + ETB R / Rp 1/2 14 1.814 20.955 19.793 18.631 8.2 20.442 ISO 7-1 sample + ETB/Wikipedia R / Rp 3/4 14 1.814 26.441 25.279 24.117 9.5 25.847 ISO 7-1 sample + ETB/Wikipedia R / Rp 1 11 2.309 33.249 31.77 30.291 10.4 32.599 ISO 7-1 sample + ETB/Wikipedia R / Rp 1-1/4 11 2.309 41.91 40.431 38.952 12.7 41.116 ISO 7-1 sample + ETB R / Rp 1-1/2 11 2.309 47.803 46.324 44.845 12.7 47.009 ISO 7-1 sample + ETB R / Rp 2 11 2.309 59.614 58.135 56.656 15.9 58.620 ISO 7-1 sample + ETB/Wikipedia R / Rp 2-1/2 11 2.309 75.184 73.705 72.226 17.5 74.090 ISO 7-1 sample + ETB R / Rp 3 11 2.309 87.884 86.405 84.926 20.6 86.597 ISO 7-1 sample + ETB/Wikipedia R / Rp 4 11 2.309 113.03 111.551 110.072 25.4 111.442 ISO 7-1 sample; a from ETB only R / Rp 5 11 2.309 138.43 136.951 135.472 28.6 136.643 ISO 7-1 sample; a from ETB only R / Rp 6 11 2.309 163.83 162.351 160.872 28.6 162.043 ISO 7-1 sample; a from Wikipedia only Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - iTeh Standards: ISO 7-1:1982 sample: Table 1 basic dimensions of pipe threads (pitch, d, d2, d1) 1/16 to 6 — web — Publisher's page; dimensions are facts — https://cdn.standards.iteh.ai/samples/3583/8bb5ad0f36684c6cbebd554338fcde0d/ISO-7-1-1982.pdf - Engineering ToolBox: ISO 7-1 and ISO 228 pipe threads: TPI, pitch, diameters and gauge length (a) — web — Publisher's page; dimensions are facts — https://engineeringtoolbox.com/iso-threads-d_752.html - Wikipedia: British Standard Pipe: G / R size table (major and minor diameters, gauge length) — web — Publisher's page; dimensions are facts — https://en.wikipedia.org/wiki/British_Standard_Pipe - Valves Tubes Fittings: BS EN 10255 steel tube: nominal bore, OD and wall (light / medium / heavy) — web — Publisher's page; dimensions are facts — https://www.valvestubesfittings.com/data/pdf/steel-tube/bs-en10255-steel-tube-technical-specifications-weight-dimensions-pressure.pdf - Engineering ToolBox: BS 1387 steel tubes: nominal bore, OD and wall (light / medium / heavy) — web — Publisher's page; dimensions are facts — https://engineeringtoolbox.com/bs1387-steel-tubes-dimensions-d_97.html Free files (CC BY 4.0, Xem Studio; STEP + STL, 8 parts): https://xemstudio.com/files/hardware/bsp-taper-pipe-threads-r-rp-iso-7-1/index.json API: https://xemstudio.com/api/geometry?object=bsp-taper-pipe-threads-r-rp-iso-7-1