NPT pipe plugs: square head, hex head, round head and hex socket (ASME B16.11; Dryseal NPTF, flush PTF) 1/16 to 6 in — head size, length, socket + envelope models — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/pipe-plugs-npt-square-hex-socket/ (sheet CC BY 4.0) Basis: Penn Machine's forged square head plug catalog (inches), wermac.org's ASME B16.11 plug tables (mm), and Alma Bolt's and American Fastener's hex socket plug sheets (inches); 18 hex-socket plug envelopes as files Catalog version: 2026-10-20 Overall (mm): length 7.9, width 7.9, height 8.2 - Square head plugs (forged steel, ASME B16.11 family), Penn Machine, inches, 1/8 to 6: A, B, C and the thread length L, with weights. The text read does not define the letters. They were matched to wermac.org's mm table: Penn A tracks wermac's B (width across flats: 1/2 → 0.563 in = 14.3 mm against 14; 1 → 0.813 in = 20.6 mm against 21; 2 → 1.313 in = 33.3 mm against 32), Penn B tracks wermac's E (length: 3/4 → 0.625 in = 15.9 against 16; 2 → 0.880 in = 22.4 against 22) and Penn C tracks wermac's C (square height: 1/2 → 0.380 in = 9.7 mm against 10). That matching is the Xem reading, not a statement of either source. At 4 in Penn's A is 2.500 in (63.5 mm) against wermac's 65 mm. The mm tables are minimum values (wermac: 'min'), so small differences are expected. - wermac.org tables are third-party transcriptions of ASME B16.11 plugs, mm, NPS 1/2 to 4, with the page's own letters; there is no hex-socket table on that page (hex-socket plugs are not an ASME B16.11 product in the sources read). In the round head table the 2-1/2 length E is 37 where hex and square give 27; probably a typo, shown as printed. A hex-head table from a cast stainless catalog (150# CSS) was read but its columns could not be assigned, so it is not used. - Hex socket plugs: Alma Bolt prints two series with the same columns, Dryseal NPTF (1/16 to 2) and flush PTF (1/16 to 1-1/4): OD D, threads per inch, hex socket J (across flats), key engagement T (min), wall G (min), overall length L (max / min), tightening torque, tap drill. American Fastener's flush-seal sheet has the same numbers as Alma's PTF rows. Alma does not define L or G; American Fastener's headers are compressed, so L as overall length and G as wall thickness follow the order of its columns. Alma heads the NPTF table 'tapered 3/4 in diameter per foot' and the flush PTF table 'tapered 7/8 in diameter per foot'. See npt-thread-dimensions-asme-b1-20-1 for the thread numbers. - Files: straight cylinders at the OD D with the L max overall length and a flat-bottomed hex socket of J across flats and T min depth, 10 Dryseal NPTF sizes and 8 flush PTF sizes. The real thread is tapered; here the printed OD D is carried as a plain cylinder at that diameter (taper not drawn). Square-head and hex-head plugs have no file: their head edges, chamfers and thread dimensions are not given as numbers that define the shape. Countersunk hex head plugs are not tabulated (no source read). - McMaster-Carr sells pipe plugs (square, hex head, socket, SAE J531 etc.) with per-part STEP; its SAE J531 and steel socket plug categories are linked, not copied. table (source) NPS TPI across flats / OD head height length / thread length key engagement T wall G torque tap drill note square head plug, Penn Machine (in) 1/8 — A 0.281 C 0.250 B 0.380; thread L 0.273 — — — — letters as printed; weight (carbon steel) 0.02 lb square head plug, Penn Machine (in) 1/4 — A 0.380 C 0.250 B 0.440; thread L 0.395 — — — — letters as printed; weight (carbon steel) 0.03 lb square head plug, Penn Machine (in) 3/8 — A 0.440 C 0.313 B 0.500; thread L 0.407 — — — — letters as printed; weight (carbon steel) 0.06 lb square head plug, Penn Machine (in) 1/2 — A 0.563 C 0.380 B 0.563; thread L 0.534 — — — — letters as printed; weight (carbon steel) 0.11 lb square head plug, Penn Machine (in) 3/4 — A 0.625 C 0.440 B 0.625; thread L 0.553 — — — — letters as printed; weight (carbon steel) 0.18 lb square head plug, Penn Machine (in) 1 — A 0.813 C 0.500 B 0.750; thread L 0.661 — — — — letters as printed; weight (carbon steel) 0.35 lb square head plug, Penn Machine (in) 1-1/4 — A 0.940 C 0.563 B 0.813; thread L 0.681 — — — — letters as printed; weight (carbon steel) 0.6 lb square head plug, Penn Machine (in) 1-1/2 — A 1.125 C 0.625 B 0.813; thread L 0.681 — — — — letters as printed; weight (carbon steel) 0.82 lb square head plug, Penn Machine (in) 2 — A 1.313 C 0.690 B 0.880; thread L 0.697 — — — — letters as printed; weight (carbon steel) 1.36 lb square head plug, Penn Machine (in) 2-1/2 — A 1.500 C 0.750 B 1.063; thread L 0.933 — — — — letters as printed; weight (carbon steel) 2.21 lb square head plug, Penn Machine (in) 3 — A 1.690 C 0.813 B 1.125; thread L 1.016 — — — — letters as printed; weight (carbon steel) 3.47 lb square head plug, Penn Machine (in) 3-1/2 — A 1.875 C 0.875 B 1.187; thread L 1.071 — — — — letters as printed; weight (carbon steel) 4.73 lb square head plug, Penn Machine (in) 4 — A 2.500 C 1.000 B 1.250; thread L 1.094 — — — — letters as printed; weight (carbon steel) 8.64 lb square head plug, Penn Machine (in) 5 — A 3.250 C 1.625 B 1.875; thread L 1.187 — — — — letters as printed; weight (carbon steel) 17.12 lb square head plug, Penn Machine (in) 6 — A 4.250 C 1.875 B 2.000; thread L 1.208 — — — — letters as printed; weight (carbon steel) 28.41 lb square head plug, ASME B16.11 (wermac, mm) 1/2 — B min 14 C min 10 E min length 14 — — — — wermac letters: B across flats, C square height, E length square head plug, ASME B16.11 (wermac, mm) 3/4 — B min 16 C min 11 E min length 16 — — — — wermac letters: B across flats, C square height, E length square head plug, ASME B16.11 (wermac, mm) 1 — B min 21 C min 13 E min length 19 — — — — wermac letters: B across flats, C square height, E length square head plug, ASME B16.11 (wermac, mm) 1-1/4 — B min 24 C min 14 E min length 21 — — — — wermac letters: B across flats, C square height, E length square head plug, ASME B16.11 (wermac, mm) 1-1/2 — B min 28 C min 16 E min length 21 — — — — wermac letters: B across flats, C square height, E length square head plug, ASME B16.11 (wermac, mm) 2 — B min 32 C min 18 E min length 22 — — — — wermac letters: B across flats, C square height, E length square head plug, ASME B16.11 (wermac, mm) 2-1/2 — B min 36 C min 19 E min length 27 — — — — wermac letters: B across flats, C square height, E length square head plug, ASME B16.11 (wermac, mm) 3 — B min 41 C min 21 E min length 28 — — — — wermac letters: B across flats, C square height, E length square head plug, ASME B16.11 (wermac, mm) 4 — B min 65 C min 25 E min length 32 — — — — wermac letters: B across flats, C square height, E length hex head plug, ASME B16.11 (wermac, mm) 1/2 — F nominal 22 J min 8 E min length 14 — — — — wermac letters; F read as the hex width hex head plug, ASME B16.11 (wermac, mm) 3/4 — F nominal 27 J min 10 E min length 16 — — — — wermac letters; F read as the hex width hex head plug, ASME B16.11 (wermac, mm) 1 — F nominal 35 J min 10 E min length 19 — — — — wermac letters; F read as the hex width hex head plug, ASME B16.11 (wermac, mm) 1-1/4 — F nominal 44.5 J min 14 E min length 21 — — — — wermac letters; F read as the hex width hex head plug, ASME B16.11 (wermac, mm) 1-1/2 — F nominal 51 J min 16 E min length 21 — — — — wermac letters; F read as the hex width hex head plug, ASME B16.11 (wermac, mm) 2 — F nominal 63.5 J min 18 E min length 22 — — — — wermac letters; F read as the hex width hex head plug, ASME B16.11 (wermac, mm) 2-1/2 — F nominal 76 J min 19 E min length 27 — — — — wermac letters; F read as the hex width hex head plug, ASME B16.11 (wermac, mm) 3 — F nominal 89 J min 21 E min length 28 — — — — wermac letters; F read as the hex width hex head plug, ASME B16.11 (wermac, mm) 4 — F nominal 117.5 J min 25 E min length 32 — — — — wermac letters; F read as the hex width round head plug, ASME B16.11 (wermac, mm) 1/2 — D head dia 21 — E min length 14; A min length 44 — — — — wermac prints E = 37 at 2-1/2, against 27 for hex / square: probably a typo round head plug, ASME B16.11 (wermac, mm) 3/4 — D head dia 27 — E min length 16; A min length 44 — — — — wermac prints E = 37 at 2-1/2, against 27 for hex / square: probably a typo round head plug, ASME B16.11 (wermac, mm) 1 — D head dia 33 — E min length 19; A min length 51 — — — — wermac prints E = 37 at 2-1/2, against 27 for hex / square: probably a typo round head plug, ASME B16.11 (wermac, mm) 1-1/4 — D head dia 43 — E min length 21; A min length 51 — — — — wermac prints E = 37 at 2-1/2, against 27 for hex / square: probably a typo round head plug, ASME B16.11 (wermac, mm) 1-1/2 — D head dia 48 — E min length 21; A min length 51 — — — — wermac prints E = 37 at 2-1/2, against 27 for hex / square: probably a typo round head plug, ASME B16.11 (wermac, mm) 2 — D head dia 60 — E min length 22; A min length 64 — — — — wermac prints E = 37 at 2-1/2, against 27 for hex / square: probably a typo round head plug, ASME B16.11 (wermac, mm) 2-1/2 — D head dia 73 — E min length 37; A min length 70 — — — — wermac prints E = 37 at 2-1/2, against 27 for hex / square: probably a typo round head plug, ASME B16.11 (wermac, mm) 3 — D head dia 89 — E min length 28; A min length 70 — — — — wermac prints E = 37 at 2-1/2, against 27 for hex / square: probably a typo round head plug, ASME B16.11 (wermac, mm) 4 — D head dia 114 — E min length 32; A min length 76 — — — — wermac prints E = 37 at 2-1/2, against 27 for hex / square: probably a typo hex socket plug, Dryseal NPTF (Alma, in) 1/16 27 OD D 0.312 J 5/32 L 0.300 – 0.324 T min 0.140 G min 0.062 150 in-lb 15/64 letters as printed by Alma (L, G not defined) hex socket plug, Dryseal NPTF (Alma, in) 1/8 27 OD D 0.405 J 3/16 L 0.300 – 0.324 T min 0.140 G min 0.062 250 in-lb 21/64 letters as printed by Alma (L, G not defined) hex socket plug, Dryseal NPTF (Alma, in) 1/4 18 OD D 0.540 J 1/4 L 0.417 – 0.457 T min 0.218 G min 0.073 600 in-lb 27/64 letters as printed by Alma (L, G not defined) hex socket plug, Dryseal NPTF (Alma, in) 3/8 18 OD D 0.675 J 5/16 L 0.480 – 0.520 T min 0.250 G min 0.084 1200 in-lb 7/16 letters as printed by Alma (L, G not defined) hex socket plug, Dryseal NPTF (Alma, in) 1/2 14 OD D 0.840 J 3/8 L 0.542 – 0.582 T min 0.312 G min 0.095 1800 in-lb 9/16 letters as printed by Alma (L, G not defined) hex socket plug, Dryseal NPTF (Alma, in) 3/4 14 OD D 1.050 J 9/16 L 0.605 – 0.645 T min 0.312 G min 0.125 3000 in-lb 57/64 letters as printed by Alma (L, G not defined) hex socket plug, Dryseal NPTF (Alma, in) 1 11-1/2 OD D 1.315 J 5/8 L 0.730 – 0.770 T min 0.375 G min 0.125 4200 in-lb 1-1/8 letters as printed by Alma (L, G not defined) hex socket plug, Dryseal NPTF (Alma, in) 1-1/4 11-1/2 OD D 1.660 J 3/4 L 0.792 – 0.832 T min 0.437 G min 0.156 5400 in-lb 37.5 mm letters as printed by Alma (L, G not defined) hex socket plug, Dryseal NPTF (Alma, in) 1-1/2 11-1/2 OD D 1.900 J 1 L 0.780 – 0.843 T min 0.437 G min 0.156 6900 in-lb 43.5 mm letters as printed by Alma (L, G not defined) hex socket plug, Dryseal NPTF (Alma, in) 2 11-1/2 OD D 2.375 J 1 L 0.844 – 0.906 T min 0.437 G min 0.156 8500 in-lb 2-3/16 letters as printed by Alma (L, G not defined) hex socket plug, flush PTF (Alma, American Fastener, in) 1/16 27 OD D 0.307 J 5/32 L 0.235 – 0.250 T min 0.140 G min 0.052 150 in-lb 15/64 same numbers on both sheets hex socket plug, flush PTF (Alma, American Fastener, in) 1/8 27 OD D 0.401 J 3/16 L 0.235 – 0.250 T min 0.140 G min 0.049 250 in-lb 21/64 same numbers on both sheets hex socket plug, flush PTF (Alma, American Fastener, in) 1/4 18 OD D 0.529 J 1/4 L 0.391 – 0.406 T min 0.218 G min 0.045 600 in-lb 27/64 same numbers on both sheets hex socket plug, flush PTF (Alma, American Fastener, in) 3/8 18 OD D 0.667 J 5/16 L 0.391 – 0.406 T min 0.250 G min 0.040 1200 in-lb 9/16 same numbers on both sheets hex socket plug, flush PTF (Alma, American Fastener, in) 1/2 14 OD D 0.830 J 3/8 L 0.516 – 0.531 T min 0.312 G min 0.067 1800 in-lb 9/16 same numbers on both sheets hex socket plug, flush PTF (Alma, American Fastener, in) 3/4 14 OD D 1.041 J 9/16 L 0.516 – 0.531 T min 0.312 G min 0.054 3000 in-lb 57/64 same numbers on both sheets hex socket plug, flush PTF (Alma, American Fastener, in) 1 11-1/2 OD D 1.302 J 5/8 L 0.641 – 0.656 T min 0.375 G min 0.112 4200 in-lb 1-1/8 same numbers on both sheets hex socket plug, flush PTF (Alma, American Fastener, in) 1-1/4 11-1/2 OD D 1.647 J 3/4 L 0.641 – 0.656 T min 0.437 G min 0.102 5400 in-lb 37.5 mm same numbers on both sheets Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - Pennsylvania Machine Works (Penn Machine): Forged steel square head plug: pipe size 1/8 to 6, dimensions A, B, C, weight and thread length L, inches — web — Maker catalog; numbers only. Letters A / B / C are not defined in the text read — https://www.cooneybrothers.com/userfiles/ad/documents/Pennsylvania_12203304_Catalog.pdf - wermac.org: Threaded plugs (ASME B16.11): hex head, square head and round head plug dimensions in mm, NPS 1/2 to 4 — web — Third-party reference; numbers only. No hex-socket table on the page — https://www.wermac.org/fittings/dim_thd_plugs.html - Alma Bolt: Hex socket pressure plugs: Dryseal NPTF (1/16 to 2) and flush PTF (1/16 to 1-1/4): D, TPI, J hex socket, T key engagement, G wall, L max / min, torque, tap drill — web — Distributor catalog; numbers only. The page does not define the L and G letters — https://www.almabolt.com/pages/catalog/alloysocket/hexpressureplugs.htm - American Fastener: Socket pipe plug, flush seal: nominal size, OD, TPI, hex socket size, key engagement, wall, overall length max / min, tightening torque, 1/16 to 1-1/4 — web — Maker data sheet; numbers only. No standard cited — https://www.americanfastener.com/wp-content/uploads/2020/06/SOCKETS-SOCKET-PIPE-PLUG-FLUSH-SEAL-AMERICAN-FASTENER.pdf - McMaster-Carr: SAE J531 pipe plugs (free STEP/IGES per part, for your own design use; no redistribution) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution [verify license at link] — https://www.mcmaster.com/products/pipe-plugs/specifications-met~sae-j531/ - McMaster-Carr: Steel socket pipe fitting plugs (free STEP/IGES per part, for your own design use; no redistribution) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution [verify license at link] — https://www.mcmaster.com/products/socket-pipe-fitting-plugs/material~steel-2/ Free files (CC BY 4.0, Xem Studio; STEP + STL, 18 parts): https://xemstudio.com/files/hardware/pipe-plugs-npt-square-hex-socket/index.json API: https://xemstudio.com/api/geometry?object=pipe-plugs-npt-square-hex-socket