{
 "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-hot-gasket",
 "name": "Tri-clamp flat gasket (hot joint, bore ID): 1.7 mm ring, ½ to 4 in",
 "kind": "hardware",
 "category": "Stirling engines",
 "group": "Tri-clamp engine parts",
 "year": null,
 "question": "What flat gasket goes in a hot tri-clamp joint?",
 "tags": [
  "tri-clamp",
  "gasket",
  "hot joint",
  "flat gasket",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "high temperature tri clamp gasket",
  "flat tri clamp gasket",
  "hot tri clamp joint",
  "tri clamp gasket 2 inch flat"
 ],
 "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/tri-clamp-hot-gasket/",
 "sheet_txt": "https://xemstudio.com/objects/tri-clamp-hot-gasket/sheet.txt",
 "sheet": {
  "basis": "Flat ring: OD = C3 − 1 (flange less 0.5 per side), ID = tube bore, 1.7 mm thick (the ISO 2852 Type B web, the gap the clamp groove is drawn for)",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "A flat 1.7 mm ring that takes the place of the Type B gasket at a joint that runs too hot for an elastomer gasket, such as the flame end of a Stirling engine, or wherever a piston or displacer has to pass through the joint (its ID is the bore, so there is no lip in the way).",
   "OD is the flange diameter less 1 mm (Ø24.0 / 49.5 / 63.0 / 76.5 / 90.0 / 118.0); ID is the bore of the larger tube on that flange (Ø15.75 / 34.8 / 47.5 / 60.2 / 72.9 / 97.38).",
   "Thickness 1.7 mm is the Type B gasket's web, so the clamp's groove meets the rims after the same 0.4 mm of travel as at a Type B joint and the last 0.6 mm per half squeezes the ring (designed); a thinner ring would leave the clamp unable to reach the rims."
  ],
  "table": {
   "columns": [
    "size_in",
    "od_mm",
    "id_mm",
    "thickness_mm"
   ],
   "rows": [
    [
     "½–¾",
     24,
     15.75,
     1.7
    ],
    [
     "1–1½",
     49.5,
     34.8,
     1.7
    ],
    [
     "2",
     63,
     47.5,
     1.7
    ],
    [
     "2½",
     76.5,
     60.2,
     1.7
    ],
    [
     "3",
     90,
     72.9,
     1.7
    ],
    [
     "4",
     118,
     97.38,
     1.7
    ]
   ]
  }
 },
 "sheet_text": "Tri-clamp flat gasket (hot joint, bore ID): 1.7 mm ring, ½ to 4 in — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/tri-clamp-hot-gasket/  (CC BY 4.0)\nBasis: Flat ring: OD = C3 − 1 (flange less 0.5 per side), ID = tube bore, 1.7 mm thick (the ISO 2852 Type B web, the gap the clamp groove is drawn for)\nCatalog version: 2026-10-20\n\nSizes: see table below\n- A flat 1.7 mm ring that takes the place of the Type B gasket at a joint that runs too hot for an elastomer gasket, such as the flame end of a Stirling engine, or wherever a piston or displacer has to pass through the joint (its ID is the bore, so there is no lip in the way).\n- OD is the flange diameter less 1 mm (Ø24.0 / 49.5 / 63.0 / 76.5 / 90.0 / 118.0); ID is the bore of the larger tube on that flange (Ø15.75 / 34.8 / 47.5 / 60.2 / 72.9 / 97.38).\n- Thickness 1.7 mm is the Type B gasket's web, so the clamp's groove meets the rims after the same 0.4 mm of travel as at a Type B joint and the last 0.6 mm per half squeezes the ring (designed); a thinner ring would leave the clamp unable to reach the rims.\n\nsize_in  od_mm  id_mm  thickness_mm\n½–¾  24.0  15.75  1.7\n1–1½  49.5  34.8  1.7\n2  63.0  47.5  1.7\n2½  76.5  60.2  1.7\n3  90.0  72.9  1.7\n4  118.0  97.38  1.7\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- ISO: ISO 2852:1993 Stainless steel clamp pipe couplings for the food industry — standard — ISO [verify license at link] — https://www.iso.org/standard/7873.html\n- Long Earth Society: Tri-clamp Stirling 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/tri-clamp-hot-gasket/index.json\nAPI: https://xemstudio.com/api/geometry?object=tri-clamp-hot-gasket\n",
 "sources": [
  {
   "publisher": "ISO",
   "title": "ISO 2852:1993 Stainless steel clamp pipe couplings for the food industry",
   "url": "https://www.iso.org/standard/7873.html",
   "formats": [
    "standard"
   ],
   "license": "ISO",
   "license_verified": false,
   "hosted": false
  },
  {
   "publisher": "Long Earth Society",
   "title": "Tri-clamp Stirling 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-clamps",
  "tri-clamp-gasket",
  "tri-clamp-heat-shield",
  "sanitary-clamp-gaskets",
  "tri-clamp-ferrule"
 ],
 "fits": [
  {
   "role": "Goes in or on",
   "items": [
    {
     "slug": "tri-clamp-ferrule",
     "why": "on the lands between two faces"
    }
   ]
  },
  {
   "role": "Connects to",
   "items": [
    {
     "slug": "tri-clamp-clamps",
     "why": "the clamp squeezes it"
    }
   ]
  },
  {
   "role": "Alternatives",
   "items": [
    {
     "slug": "tri-clamp-gasket",
     "why": "Type B elastomer gasket for cool joints"
    }
   ]
  },
  {
   "role": "Also needed",
   "items": [
    {
     "slug": "tri-clamp-heat-shield",
     "why": "shield between the flame and the clamp"
    }
   ]
  }
 ],
 "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": "hot-gasket ring",
   "exact": "C3 − 1 × bore × 1.7 (the Type B web)",
   "mates": "ferrule faces; the clamp squeezes it in its last 0.6 mm",
   "fit": "designed",
   "files": "hot-gasket-"
  }
 ],
 "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": "What size is a 2 inch flat hot gasket?",
   "a": "Ø63.0 OD × Ø47.5 ID × 1.7 mm."
  },
  {
   "q": "Why a flat gasket at a hot joint?",
   "a": "The Type B gasket is an elastomer with a bead in the face recesses and a lip into the bore; the flat ring has neither and sits on the lands, for a joint too hot for the elastomer or a joint a piston has to pass."
  },
  {
   "q": "Why is the flat gasket 1.7 mm thick?",
   "a": "That is the Type B web thickness the two-bolt clamp's groove is drawn for: the groove reaches the rims after 0.4 mm and squeezes the ring in the last 0.6 mm of travel."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "hot-gasket-0.75in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-0.75in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-0.75in.stl",
   "note": "0.75 in flat gasket: Ø24 OD × Ø15.8 ID (= the bore) × 1.7 (the Type B web), sits flat on the lands in place of the Type B gasket at a flame-side joint or wherever a piston or displacer must pass the joint"
  },
  {
   "file": "hot-gasket-1.5in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-1.5in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-1.5in.stl",
   "note": "1.5 in flat gasket: Ø49.5 OD × Ø34.8 ID (= the bore) × 1.7 (the Type B web), sits flat on the lands in place of the Type B gasket at a flame-side joint or wherever a piston or displacer must pass the joint"
  },
  {
   "file": "hot-gasket-2in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-2in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-2in.stl",
   "note": "2 in flat gasket: Ø63 OD × Ø47.5 ID (= the bore) × 1.7 (the Type B web), sits flat on the lands in place of the Type B gasket at a flame-side joint or wherever a piston or displacer must pass the joint"
  },
  {
   "file": "hot-gasket-2.5in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-2.5in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-2.5in.stl",
   "note": "2.5 in flat gasket: Ø76.5 OD × Ø60.2 ID (= the bore) × 1.7 (the Type B web), sits flat on the lands in place of the Type B gasket at a flame-side joint or wherever a piston or displacer must pass the joint"
  },
  {
   "file": "hot-gasket-3in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-3in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-3in.stl",
   "note": "3 in flat gasket: Ø90 OD × Ø72.9 ID (= the bore) × 1.7 (the Type B web), sits flat on the lands in place of the Type B gasket at a flame-side joint or wherever a piston or displacer must pass the joint"
  },
  {
   "file": "hot-gasket-4in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-4in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-4in.stl",
   "note": "4 in flat gasket: Ø118 OD × Ø97.4 ID (= the bore) × 1.7 (the Type B web), sits flat on the lands in place of the Type B gasket at a flame-side joint or wherever a piston or displacer must pass the joint"
  }
 ],
 "markdown": "https://xemstudio.com/objects/tri-clamp-hot-gasket/index.md"
}