{
 "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": "spool-hanger-collars",
 "name": "Spool hanger collars: clamp a tri-clamp spool to 2020 extrusion over the flame (1.5, 2, 3 in)",
 "kind": "hardware",
 "category": "Stirling engines",
 "group": "Tri-clamp engine parts",
 "year": null,
 "question": "How do I hold a tri-clamp Stirling engine upright over a flame?",
 "tags": [
  "tri-clamp",
  "stand",
  "mount",
  "2020",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "tri clamp spool stand",
  "mount stirling cylinder to 2020",
  "tri clamp tube clamp bracket",
  "stirling engine stand"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 6,
 "url": "https://xemstudio.com/objects/spool-hanger-collars/",
 "sheet_txt": "https://xemstudio.com/objects/spool-hanger-collars/sheet.txt",
 "sheet": {
  "basis": "16 ga tube OD (38.1 / 50.8 / 76.2) from the tri-clamp spool entry; 2020 slot pitch for the mounting tab",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "A split collar bored to the tube OD with a 1 mm split each side, closed with two M4 screws, holds the spool anywhere along its cold half; the bar half takes two M5 screws and T-nuts into a horizontal 2020 crossbar between two uprights, so a vertical beta, free-piston or thermoacoustic engine hangs with its hot end over a tea light or burner and the base stays cool.",
   "Clamp on the cold side only; two collars on two uprights for a long spool. For a horizontal gamma use the base plate instead.",
   "LES: how the vertical engines stand."
  ],
  "table": {
   "columns": [
    "size",
    "tube_od_mm",
    "collar_id_mm",
    "width_mm",
    "closure",
    "mount"
   ],
   "rows": [
    [
     "1.5",
     38.1,
     38.1,
     16,
     "2 × M4 × 30 + nuts",
     "2 × M5 at 66.1 mm to a 2020 crossbar"
    ],
    [
     "2",
     50.8,
     50.8,
     16,
     "2 × M4 × 30 + nuts",
     "2 × M5 at 78.8 mm to a 2020 crossbar"
    ],
    [
     "3",
     76.2,
     76.2,
     16,
     "2 × M4 × 30 + nuts",
     "2 × M5 at 104.2 mm to a 2020 crossbar"
    ]
   ]
  }
 },
 "sheet_text": "Spool hanger collars: clamp a tri-clamp spool to 2020 extrusion over the flame (1.5, 2, 3 in) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/spool-hanger-collars/  (CC BY 4.0)\nBasis: 16 ga tube OD (38.1 / 50.8 / 76.2) from the tri-clamp spool entry; 2020 slot pitch for the mounting tab\nCatalog version: 2026-10-20\n\nSizes: see table below\n- A split collar bored to the tube OD with a 1 mm split each side, closed with two M4 screws, holds the spool anywhere along its cold half; the bar half takes two M5 screws and T-nuts into a horizontal 2020 crossbar between two uprights, so a vertical beta, free-piston or thermoacoustic engine hangs with its hot end over a tea light or burner and the base stays cool.\n- Clamp on the cold side only; two collars on two uprights for a long spool. For a horizontal gamma use the base plate instead.\n- LES: how the vertical engines stand.\n\nsize  tube_od_mm  collar_id_mm  width_mm  closure  mount\n1.5  38.1  38.1  16  2 × M4 × 30 + nuts  2 × M5 at 66.1 mm to a 2020 crossbar\n2  50.8  50.8  16  2 × M4 × 30 + nuts  2 × M5 at 78.8 mm to a 2020 crossbar\n3  76.2  76.2  16  2 × M4 × 30 + nuts  2 × M5 at 104.2 mm to a 2020 crossbar\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\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, 6 parts): https://xemstudio.com/files/hardware/spool-hanger-collars/index.json\nAPI: https://xemstudio.com/api/geometry?object=spool-hanger-collars\n",
 "sources": [
  {
   "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": [
  "t-slot-extrusions",
  "t-slot-brackets-and-nuts",
  "tri-clamp-spool",
  "tri-clamp-cups",
  "gamma-base-plate-and-beam"
 ],
 "fits": [
  {
   "role": "Goes in or on",
   "items": [
    {
     "slug": "tri-clamp-spool",
     "why": "clamps the 16 ga tube"
    },
    {
     "slug": "tri-clamp-cups",
     "why": "same tube OD"
    }
   ]
  },
  {
   "role": "Connects to",
   "items": [
    {
     "slug": "t-slot-extrusions",
     "why": "bolts to a 2020 crossbar"
    }
   ]
  },
  {
   "role": "Alternatives",
   "items": [
    {
     "slug": "gamma-base-plate-and-beam",
     "why": "horizontal engines sit on the base plate"
    }
   ]
  },
  {
   "role": "Also needed",
   "items": [
    {
     "slug": "t-slot-brackets-and-nuts",
     "why": "M5 T-nuts, corner brackets"
    },
    {
     "slug": "socket-head-cap-screws-metric",
     "why": "M4 × 30 and M5 screws"
    }
   ]
  }
 ],
 "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": "collar bore",
   "exact": "tube OD (38.1 / 50.8 / 76.2)",
   "mates": "tri-clamp tube; the split closes on it",
   "fit": "clamp",
   "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": "How do I mount a vertical tri-clamp Stirling engine?",
   "a": "Clamp a spool hanger collar around the cold half of the tube and bolt its bar to a horizontal 2020 crossbar with two M5 screws and T-nuts; the hot end hangs over the flame."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "hanger-1.5in-tab",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spool-hanger-collars/hanger-1.5in-tab.step",
   "stl": "https://xemstudio.com/files/hardware/spool-hanger-collars/hanger-1.5in-tab.stl",
   "note": "1.5 in spool hanger, half with the mounting bar: clamps the Ø38.1 tube; 2 × M5 at 66.1 mm centres into a horizontal 2020 crossbar's slot"
  },
  {
   "file": "hanger-1.5in-plain",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spool-hanger-collars/hanger-1.5in-plain.step",
   "stl": "https://xemstudio.com/files/hardware/spool-hanger-collars/hanger-1.5in-plain.stl",
   "note": "1.5 in spool hanger, plain half: 2 × M4 × 30 close it on the tube"
  },
  {
   "file": "hanger-2in-tab",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spool-hanger-collars/hanger-2in-tab.step",
   "stl": "https://xemstudio.com/files/hardware/spool-hanger-collars/hanger-2in-tab.stl",
   "note": "2 in spool hanger, half with the mounting bar: clamps the Ø50.8 tube; 2 × M5 at 78.8 mm centres into a horizontal 2020 crossbar's slot"
  },
  {
   "file": "hanger-2in-plain",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spool-hanger-collars/hanger-2in-plain.step",
   "stl": "https://xemstudio.com/files/hardware/spool-hanger-collars/hanger-2in-plain.stl",
   "note": "2 in spool hanger, plain half: 2 × M4 × 30 close it on the tube"
  },
  {
   "file": "hanger-3in-tab",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spool-hanger-collars/hanger-3in-tab.step",
   "stl": "https://xemstudio.com/files/hardware/spool-hanger-collars/hanger-3in-tab.stl",
   "note": "3 in spool hanger, half with the mounting bar: clamps the Ø76.2 tube; 2 × M5 at 104.2 mm centres into a horizontal 2020 crossbar's slot"
  },
  {
   "file": "hanger-3in-plain",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/spool-hanger-collars/hanger-3in-plain.step",
   "stl": "https://xemstudio.com/files/hardware/spool-hanger-collars/hanger-3in-plain.stl",
   "note": "3 in spool hanger, plain half: 2 × M4 × 30 close it on the tube"
  }
 ],
 "markdown": "https://xemstudio.com/objects/spool-hanger-collars/index.md"
}