{
 "version": "2026-10-20",
 "license": "Dimension sheets are written by Xem Studio from the cited sources and are free to use (CC BY 4.0, attribute 'Xem Studio'). Linked files belong to their publishers under the license shown; Xem Studio does not host them. 'license_verified: false' means the license shown is from memory or the publisher's page as last read and should be confirmed at the link before commercial use.",
 "slug": "tri-clamp-spool-npt-bosses",
 "name": "2 in × 6 in spool with three 1/4 NPT bosses at mid-length",
 "kind": "hardware",
 "category": "Hardware",
 "group": "Stirling & thermoacoustic",
 "year": null,
 "question": "How do I put gauge, fill and relief ports on a tri-clamp spool?",
 "tags": [
  "spool",
  "npt",
  "port",
  "gauge",
  "relief",
  "custom spool",
  "tri-clamp",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "tri clamp spool with npt port",
  "sanitary spool gauge port",
  "tri clamp instrument spool"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 1,
 "url": "https://xemstudio.com/objects/tri-clamp-spool-npt-bosses/",
 "sheet_txt": "https://xemstudio.com/objects/tri-clamp-spool-npt-bosses/sheet.txt",
 "sheet": {
  "basis": "Stock 2 in × 6 in spool; 1/4 NPT per ASME B1.20.1; boss size and positions are design values",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "A standard 2 in × 6 in spool with three welded 1/4 NPT bosses round its middle: fill valve, pressure gauge and relief valve on one charged space.",
   "On the horizontal gamma it is the bounce space behind the power piston: about 0.37 L that holds the mean charge so the piston only works against the cycle's swing."
  ],
  "table": {
   "columns": [
    "feature",
    "value"
   ],
   "rows": [
    [
     "length",
     "152.4 face to face"
    ],
    [
     "bosses",
     "3 × 1/4 NPT at mid-length, 90° / 30° / 150°"
    ],
    [
     "boss",
     "Ø22 to r 36, tap drill Ø11.1 × 12, Ø6 on"
    ]
   ]
  }
 },
 "sheet_text": "2 in × 6 in spool with three 1/4 NPT bosses at mid-length — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/tri-clamp-spool-npt-bosses/  (CC BY 4.0)\nBasis: Stock 2 in × 6 in spool; 1/4 NPT per ASME B1.20.1; boss size and positions are design values\nCatalog version: 2026-10-20\n\nSizes: see table below\n- A standard 2 in × 6 in spool with three welded 1/4 NPT bosses round its middle: fill valve, pressure gauge and relief valve on one charged space.\n- On the horizontal gamma it is the bounce space behind the power piston: about 0.37 L that holds the mean charge so the piston only works against the cycle's swing.\n\nfeature  value\nlength  152.4 face to face\nbosses  3 × 1/4 NPT at mid-length, 90° / 30° / 150°\nboss  Ø22 to r 36, tap drill Ø11.1 × 12, Ø6 on\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- ISO (via iTeh sample): ISO 2852 clamp liners: face profile and flange / groove diameters — PDF — standard excerpt; dimensions are facts — https://cdn.standards.iteh.ai/samples/7850/eb49c396488d408c8ced3e2961d76cf3/ISO-2852-1974.pdf\n- ASME: BPE Bioprocessing Equipment (clamp fitting dimensions, tube OD and wall) — standard — ASME; dimensions are facts [verify license at link] — https://www.asme.org/codes-standards/find-codes-standards/bpe-bioprocessing-equipment\n- ASME: ASME B1.20.1 Pipe Threads, General Purpose, Inch (NPT): 1/4-18 major Ø13.72, tap drill 7/16 in (11.1), L2 10.2 — standard — ASME; dimensions are facts [verify license at link] — https://www.asme.org/codes-standards/find-codes-standards/b1-20-1-pipe-threads-general-purpose-inch\n- Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/tri-clamp-spool-npt-bosses/index.json\nAPI: https://xemstudio.com/api/geometry?object=tri-clamp-spool-npt-bosses\n",
 "sources": [
  {
   "publisher": "ISO (via iTeh sample)",
   "title": "ISO 2852 clamp liners: face profile and flange / groove diameters",
   "url": "https://cdn.standards.iteh.ai/samples/7850/eb49c396488d408c8ced3e2961d76cf3/ISO-2852-1974.pdf",
   "formats": [
    "PDF"
   ],
   "license": "standard excerpt; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "ASME",
   "title": "BPE Bioprocessing Equipment (clamp fitting dimensions, tube OD and wall)",
   "url": "https://www.asme.org/codes-standards/find-codes-standards/bpe-bioprocessing-equipment",
   "formats": [
    "standard"
   ],
   "license": "ASME; dimensions are facts",
   "license_verified": false,
   "hosted": false
  },
  {
   "publisher": "ASME",
   "title": "ASME B1.20.1 Pipe Threads, General Purpose, Inch (NPT): 1/4-18 major Ø13.72, tap drill 7/16 in (11.1), L2 10.2",
   "url": "https://www.asme.org/codes-standards/find-codes-standards/b1-20-1-pipe-threads-general-purpose-inch",
   "formats": [
    "standard"
   ],
   "license": "ASME; dimensions are facts",
   "license_verified": false,
   "hosted": false
  },
  {
   "publisher": "Long Earth Society",
   "title": "Engine builds",
   "url": "https://longearthsociety.com/engineering/",
   "formats": [
    "web",
    "video"
   ],
   "license": "LES site",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "tri-clamp-rod-gland-cap",
  "list-tri-clamp-horizontal-gamma"
 ],
 "fits": [],
 "dimensions": "exact (nominal, no printing tolerance)",
 "dimension_rule": "All geometry on Xem Studio is exact (nominal, true size) with no printing tolerance. Where a part meets another part, the object lists its mating features (feature, exact size, what it mates with, fit class: press, slide, run, socket, clamp or designed). Apply your process's allowance to those features only; 'designed' gaps are part of the design and stay as drawn.",
 "mating": [
  {
   "feature": "faces",
   "exact": "ISO 2852 2 in, 152.4 face to face",
   "mates": "Type B gaskets, 2 in clamps",
   "fit": "clamp",
   "files": "all"
  },
  {
   "feature": "NPT bosses",
   "exact": "3 × 1/4-18 NPT, tap drill Ø11.1 × 12, Ø6 through",
   "mates": "fill valve, gauge, relief valve (1/4 NPT male)",
   "fit": "designed",
   "files": "all"
  }
 ],
 "fit_classes": {
  "press": "stays put: pin, tube, bearing or magnet held by interference. Typical FDM: hole +0.0 to +0.1 mm on diameter.",
  "slide": "assembles by hand and is held by a grub, pinch or clamp: shaft in a hub, rod in a socket, spigot in a bore. Typical FDM: +0.2 mm.",
  "run": "turns or slides in use: pin in a link, rod through a guide. Typical FDM: +0.3 mm.",
  "socket": "large sliding fit: syringe barrel, sleeve, bobbin in a bore. Typical FDM: +0.3 mm.",
  "clamp": "split part that closes on the mating part with screws: make it at size.",
  "designed": "a gap that is part of the design (piston fit option, displacer gap, air gap): do not change."
 },
 "faq": [
  {
   "q": "Which port is which?",
   "a": "Top: fill valve. The two at 30° and 150°: gauge and relief."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "spool-2in-6in-3x-npt14",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-spool-npt-bosses/spool-2in-6in-3x-npt14.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-spool-npt-bosses/spool-2in-6in-3x-npt14.stl",
   "note": "2 in × 6 in (152.4) spool, ISO 2852 faces, stock bore, three 1/4 NPT bosses at mid-length (90°, 30°, 150° from +X; Ø22 out to r 36, tap drill Ø11.1 × 12, Ø6 through the wall)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/tri-clamp-spool-npt-bosses/index.md"
}