{
 "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-custom-length-spools",
 "name": "Tri-clamp spools to a custom length (fabrication spec): 2 in × 340.7 and 310.7 mm, ¾ in × 146.7 and 80.4 mm",
 "kind": "hardware",
 "category": "Hardware",
 "group": "Sanitary clamp fittings",
 "year": null,
 "question": "How do I order a tri-clamp spool in a length that isn't 3, 6 or 12 inches?",
 "tags": [
  "spool",
  "custom spool",
  "fabrication",
  "ferrule",
  "tri-clamp",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "custom length tri clamp spool",
  "tri clamp spool fabrication drawing",
  "sanitary spool custom length",
  "2 inch tri clamp spool 340 mm"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 4,
 "url": "https://xemstudio.com/objects/tri-clamp-custom-length-spools/",
 "sheet_txt": "https://xemstudio.com/objects/tri-clamp-custom-length-spools/sheet.txt",
 "sheet": {
  "basis": "ASME BPE tube (2 in: Ø50.8 × 1.65; ¾ in: Ø19.05 × 1.65) and ISO 2852 ferrule faces exactly as the standard spools on this site (gen_sanitary.spool); lengths from the engine layouts in tools/gen_ta_power.py",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Plain spools: standard tube with a standard ferrule on each end, nothing else, cut to the stated face-to-face length. Any sanitary fabricator makes them from this drawing; a spool is the cheapest custom tri-clamp part there is.",
   "2 in × 340.7: the core of each unit of the double-acting ring engine (two ambient exchangers, 100 mm regenerator, hot exchanger, 180 mm buffer tube, two 8.4 spacers between the gasket lips). 2 in × 310.7: the twin-piston engine's core.",
   "¾ in × 146.7 and × 80.4: the riser pieces of each engine's ¾ in feedback line, between the instrument tee and cross.",
   "Fits: the faces are clamp faces; the 2 in bore Ø47.5 takes the exchanger inserts, screens and liners as a slide fit (Mating features)."
  ],
  "table": {
   "columns": [
    "file",
    "size_in",
    "face_to_face_mm",
    "tube_mm",
    "use"
   ],
   "rows": [
    [
     "spool-2in-340.7mm",
     2,
     340.7,
     "50.8 × 1.65",
     "ring core"
    ],
    [
     "spool-2in-310.7mm",
     2,
     310.7,
     "50.8 × 1.65",
     "twin core"
    ],
    [
     "spool-0.75in-146.7mm",
     0.75,
     146.7,
     "19.05 × 1.65",
     "ring riser"
    ],
    [
     "spool-0.75in-80.4mm",
     0.75,
     80.4,
     "19.05 × 1.65",
     "twin riser"
    ]
   ]
  }
 },
 "sheet_text": "Tri-clamp spools to a custom length (fabrication spec): 2 in × 340.7 and 310.7 mm, ¾ in × 146.7 and 80.4 mm — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/tri-clamp-custom-length-spools/  (CC BY 4.0)\nBasis: ASME BPE tube (2 in: Ø50.8 × 1.65; ¾ in: Ø19.05 × 1.65) and ISO 2852 ferrule faces exactly as the standard spools on this site (gen_sanitary.spool); lengths from the engine layouts in tools/gen_ta_power.py\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Plain spools: standard tube with a standard ferrule on each end, nothing else, cut to the stated face-to-face length. Any sanitary fabricator makes them from this drawing; a spool is the cheapest custom tri-clamp part there is.\n- 2 in × 340.7: the core of each unit of the double-acting ring engine (two ambient exchangers, 100 mm regenerator, hot exchanger, 180 mm buffer tube, two 8.4 spacers between the gasket lips). 2 in × 310.7: the twin-piston engine's core.\n- ¾ in × 146.7 and × 80.4: the riser pieces of each engine's ¾ in feedback line, between the instrument tee and cross.\n- Fits: the faces are clamp faces; the 2 in bore Ø47.5 takes the exchanger inserts, screens and liners as a slide fit (Mating features).\n\nfile  size_in  face_to_face_mm  tube_mm  use\nspool-2in-340.7mm  2  340.7  50.8 × 1.65  ring core\nspool-2in-310.7mm  2  310.7  50.8 × 1.65  twin core\nspool-0.75in-146.7mm  0.75  146.7  19.05 × 1.65  ring riser\nspool-0.75in-80.4mm  0.75  80.4  19.05 × 1.65  twin riser\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\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- 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- Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 4 parts): https://xemstudio.com/files/hardware/tri-clamp-custom-length-spools/index.json\nAPI: https://xemstudio.com/api/geometry?object=tri-clamp-custom-length-spools\n",
 "sources": [
  {
   "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": "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": "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-spool",
  "sanitary-clamp-end-caps",
  "tri-clamp-honed-cylinder-spool",
  "list-ta-ring-3x2in",
  "list-ta-twin-piston-2in"
 ],
 "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: land Ø56.5–Ø64; ¾ in: 25.0 flange), rim 2.85, 1.6 recess, 20° back",
   "mates": "standard clamp + Type B gasket",
   "fit": "clamp",
   "files": "all"
  },
  {
   "feature": "2 in bore",
   "exact": "Ø47.5 × face to face",
   "mates": "exchanger inserts (press), screen discs, spacers and liner (slide)",
   "fit": "slide",
   "files": "spool-2in-"
  },
  {
   "feature": "¾ in bore",
   "exact": "Ø15.75",
   "mates": "gas passage (no contact)",
   "fit": "designed",
   "files": "spool-0.75in-"
  }
 ],
 "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": "Can I order a spool in any length?",
   "a": "Yes: a spool is tube and two ferrules, so a sanitary fabricator cuts the tube to the face-to-face length you give."
  },
  {
   "q": "Why these lengths?",
   "a": "Each is the sum of the parts that stack inside it between the two gasket lips (2 in) or what fills a riser exactly (¾ in)."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "spool-2in-340.7mm",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-custom-length-spools/spool-2in-340.7mm.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-custom-length-spools/spool-2in-340.7mm.stl",
   "note": "2 in spool, 340.7 mm face to face, 1.65 wall, ISO 2852 ferrules both ends: the ring engine's core"
  },
  {
   "file": "spool-2in-310.7mm",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-custom-length-spools/spool-2in-310.7mm.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-custom-length-spools/spool-2in-310.7mm.stl",
   "note": "2 in spool, 310.7 mm face to face: the twin-piston engine's core"
  },
  {
   "file": "spool-0.75in-146.7mm",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-custom-length-spools/spool-0.75in-146.7mm.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-custom-length-spools/spool-0.75in-146.7mm.stl",
   "note": "¾ in spool, 146.7 mm face to face (25.0 flange): ring-engine riser"
  },
  {
   "file": "spool-0.75in-80.4mm",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-custom-length-spools/spool-0.75in-80.4mm.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-custom-length-spools/spool-0.75in-80.4mm.stl",
   "note": "¾ in spool, 80.4 mm face to face: twin-engine riser"
  }
 ],
 "markdown": "https://xemstudio.com/objects/tri-clamp-custom-length-spools/index.md"
}