{
 "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-clamps",
 "name": "Tri-clamp clamps (printable two-bolt), hot-joint gaskets and heat shields: every flange size, ½ to 4 in",
 "kind": "hardware",
 "category": "Stirling engines",
 "group": "Tri-clamp engine parts",
 "year": null,
 "question": "Can I print a tri-clamp clamp, and what gasket survives the hot end of a Stirling engine?",
 "tags": [
  "tri-clamp",
  "clamp",
  "gasket",
  "mica",
  "graphite",
  "stirling",
  "long earth society",
  "heat shield"
 ],
 "aliases": [
  "3d printed tri clamp clamp",
  "tri clamp clamp stl",
  "two bolt tri clamp",
  "high temperature tri clamp gasket",
  "mica gasket tri clamp",
  "tri clamp clamp dimensions"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 18,
 "url": "https://xemstudio.com/objects/tri-clamp-clamps/",
 "sheet_txt": "https://xemstudio.com/objects/tri-clamp-clamps/sheet.txt",
 "sheet": {
  "basis": "Groove derived from the ISO 2852 ferrule on this site: 2.85 mm rim, 20° back cone, C3 rim diameter, Type B gasket web 1.7 mm between the lands; two-bolt closure: groove contact after 0.4 mm of travel, 0.6 mm more before the halves meet (≈0.44 mm gasket squeeze)",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "The groove is the ferrule's own back cone mirrored: as the two M5 bolts pull the halves together, the 20° walls wedge the rims toward each other and squeeze the gasket. Each half has 1.0 mm to travel: the walls touch the rims after 0.4 mm and the last 0.6 mm squeezes the gasket about 0.44 mm (0.6 × tan 20° per rim) before the halves meet, so a closed gap means a seated joint.",
   "The groove follows the ISO 2852 rim, so the clamp's working temperature is set by what it is made of; at a flame-side joint the clamp has to take that joint's temperature.",
   "Hot joints: the stock silicone/EPDM gasket is good to roughly 150–200 °C.",
   "Bore over the tube: tube OD + 2 mm (no contact, designed); M5 holes Ø5.5 (ISO 273); nut traps 8 AF exact (see Mating features). Drop M5 nuts into the traps; M5 × 30 screws through both lugs. Tighten evenly until the gap between the halves is just closed on both sides.",
   "LES: the clamps and hot gaskets every tri-clamp engine on this shelf needs."
  ],
  "table": {
   "columns": [
    "size",
    "tube_od_mm",
    "rim_c3_mm",
    "clamp_od_mm",
    "clamp_width_mm",
    "groove_throat_mm",
    "contact_after_mm",
    "bolts"
   ],
   "rows": [
    [
     "0.75",
     19.1,
     25,
     34,
     13.3,
     7.4,
     0.4,
     "2 × M5 × 30 + nuts"
    ],
    [
     "1.5",
     38.1,
     50.5,
     59.5,
     15.7,
     7.4,
     0.4,
     "2 × M5 × 30 + nuts"
    ],
    [
     "2",
     50.8,
     64,
     73,
     16,
     7.4,
     0.4,
     "2 × M5 × 30 + nuts"
    ],
    [
     "2.5",
     63.5,
     77.5,
     86.5,
     16.3,
     7.4,
     0.4,
     "2 × M5 × 30 + nuts"
    ],
    [
     "3",
     76.2,
     91,
     100,
     16.5,
     7.4,
     0.4,
     "2 × M5 × 30 + nuts"
    ],
    [
     "4",
     101.6,
     119,
     128,
     17.5,
     7.4,
     0.4,
     "2 × M5 × 30 + nuts"
    ]
   ]
  }
 },
 "sheet_text": "Tri-clamp clamps (printable two-bolt), hot-joint gaskets and heat shields: every flange size, ½ to 4 in — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/tri-clamp-clamps/  (CC BY 4.0)\nBasis: Groove derived from the ISO 2852 ferrule on this site: 2.85 mm rim, 20° back cone, C3 rim diameter, Type B gasket web 1.7 mm between the lands; two-bolt closure: groove contact after 0.4 mm of travel, 0.6 mm more before the halves meet (≈0.44 mm gasket squeeze)\nCatalog version: 2026-10-20\n\nSizes: see table below\n- The groove is the ferrule's own back cone mirrored: as the two M5 bolts pull the halves together, the 20° walls wedge the rims toward each other and squeeze the gasket. Each half has 1.0 mm to travel: the walls touch the rims after 0.4 mm and the last 0.6 mm squeezes the gasket about 0.44 mm (0.6 × tan 20° per rim) before the halves meet, so a closed gap means a seated joint.\n- The groove follows the ISO 2852 rim, so the clamp's working temperature is set by what it is made of; at a flame-side joint the clamp has to take that joint's temperature.\n- Hot joints: the stock silicone/EPDM gasket is good to roughly 150–200 °C.\n- Bore over the tube: tube OD + 2 mm (no contact, designed); M5 holes Ø5.5 (ISO 273); nut traps 8 AF exact (see Mating features). Drop M5 nuts into the traps; M5 × 30 screws through both lugs. Tighten evenly until the gap between the halves is just closed on both sides.\n- LES: the clamps and hot gaskets every tri-clamp engine on this shelf needs.\n\nsize  tube_od_mm  rim_c3_mm  clamp_od_mm  clamp_width_mm  groove_throat_mm  contact_after_mm  bolts\n0.75  19.1  25.0  34.0  13.3  7.4  0.4  2 × M5 × 30 + nuts\n1.5  38.1  50.5  59.5  15.7  7.4  0.4  2 × M5 × 30 + nuts\n2  50.8  64.0  73.0  16.0  7.4  0.4  2 × M5 × 30 + nuts\n2.5  63.5  77.5  86.5  16.3  7.4  0.4  2 × M5 × 30 + nuts\n3  76.2  91.0  100.0  16.5  7.4  0.4  2 × M5 × 30 + nuts\n4  101.6  119.0  128.0  17.5  7.4  0.4  2 × M5 × 30 + nuts\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, 18 parts): https://xemstudio.com/files/hardware/tri-clamp-clamps/index.json\nAPI: https://xemstudio.com/api/geometry?object=tri-clamp-clamps\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-ferrule",
  "tri-clamp-spool",
  "tri-clamp-end-cap",
  "tri-clamp-cups",
  "hex-nuts-metric",
  "socket-head-cap-screws-metric",
  "regenerator-and-heat-materials"
 ],
 "fits": [
  {
   "role": "Goes in or on",
   "items": [
    {
     "slug": "tri-clamp-ferrule",
     "why": "groove fits the ISO 2852 rim and back cone"
    },
    {
     "slug": "tri-clamp-spool",
     "why": "any spool joint"
    }
   ]
  },
  {
   "role": "Also needed",
   "items": [
    {
     "slug": "tri-clamp-end-cap",
     "why": "Type B gasket for cold joints"
    },
    {
     "slug": "hex-nuts-metric",
     "why": "M5 nuts in the traps"
    },
    {
     "slug": "socket-head-cap-screws-metric",
     "why": "M5 × 30"
    },
    {
     "slug": "regenerator-and-heat-materials",
     "why": "mica / ceramic for the hot side"
    }
   ]
  }
 ],
 "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": "clamp groove",
   "exact": "ISO 2852 rim, 20°",
   "mates": "two ferrule rims; walls touch after 0.4 mm, 0.6 mm squeeze",
   "fit": "designed",
   "files": "clamp-half-"
  },
  {
   "feature": "nut traps",
   "exact": "M5 hex, 8 AF",
   "mates": "M5 nut",
   "fit": "press",
   "files": "clamp-half-"
  },
  {
   "feature": "hot-gasket ring",
   "exact": "C3 − 1 × bore",
   "mates": "ferrule faces",
   "fit": "designed",
   "files": "hot-gasket-"
  },
  {
   "feature": "clamp bore over the tube",
   "exact": "tube OD + 2",
   "mates": "tube (no contact)",
   "fit": "designed",
   "files": "clamp-half-"
  },
  {
   "feature": "bolt holes",
   "exact": "Ø5.5",
   "mates": "M5 screw clearance (ISO 273)",
   "fit": "designed",
   "files": "clamp-half-"
  },
  {
   "feature": "split / take-up",
   "exact": "1.0 per half, contact after 0.4",
   "mates": "the other half",
   "fit": "designed",
   "files": "clamp-half-"
  },
  {
   "feature": "heat-shield bore",
   "exact": "tube OD",
   "mates": "tri-clamp tube",
   "fit": "slide",
   "files": "heat-shield-"
  }
 ],
 "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 you 3D print a tri-clamp clamp?",
   "a": "Yes for cold joints and low pressure: print two halves of the two-bolt clamp for your size, M5 nuts in the traps, M5 × 30 screws. Its 20° groove mirrors the ferrule rims, so tightening pulls the faces together. At a flame-side joint the clamp has to take that joint's temperature."
  },
  {
   "q": "What gasket for a hot tri-clamp joint?",
   "a": "Use the flat hot-gasket ring (template here) in place of the Type B gasket on a hot joint, and the heat-shield washer between the flame and the clamp."
  },
  {
   "q": "How tight should a tri-clamp clamp be?",
   "a": "Snug the bolts evenly until the two halves just meet on both sides; the 20° groove has already squeezed the gasket by then."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "clamp-half-0.75in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-clamps/clamp-half-0.75in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/clamp-half-0.75in.stl",
   "note": "½–¾ in two-bolt clamp half (print two): 20° groove for the ISO 2852 rims, contact after 0.4 mm, 0.6 mm squeeze before the halves meet, 2 × M5 × 30 through Ø5.5 holes, nuts in 8 AF hex traps; 13.3 mm wide"
  },
  {
   "file": "hot-gasket-template-0.75in",
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    "step",
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   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
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   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-template-0.75in.stl",
   "note": "0.75 in flat hot-joint gasket"
  },
  {
   "file": "heat-shield-0.75in",
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   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/heat-shield-0.75in.stl",
   "note": "0.75 in heat shield washer Ø50 × Ø19.05 bore (= tube OD): trace on sheet, slips over the tube between flame and clamp"
  },
  {
   "file": "clamp-half-1.5in",
   "formats": [
    "step",
    "stl"
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   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/clamp-half-1.5in.stl",
   "note": "1–1½ in two-bolt clamp half (print two): 20° groove for the ISO 2852 rims, contact after 0.4 mm, 0.6 mm squeeze before the halves meet, 2 × M5 × 30 through Ø5.5 holes, nuts in 8 AF hex traps; 15.7 mm wide"
  },
  {
   "file": "hot-gasket-template-1.5in",
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   "price_usd": 0,
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   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-template-1.5in.stl",
   "note": "1.5 in flat hot-joint gasket"
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  {
   "file": "heat-shield-1.5in",
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    "step",
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   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/heat-shield-1.5in.stl",
   "note": "1.5 in heat shield washer Ø75.5 × Ø38.1 bore (= tube OD): trace on sheet, slips over the tube between flame and clamp"
  },
  {
   "file": "clamp-half-2in",
   "formats": [
    "step",
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   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/clamp-half-2in.stl",
   "note": "2 in two-bolt clamp half (print two): 20° groove for the ISO 2852 rims, contact after 0.4 mm, 0.6 mm squeeze before the halves meet, 2 × M5 × 30 through Ø5.5 holes, nuts in 8 AF hex traps; 16.0 mm wide"
  },
  {
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   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-template-2in.stl",
   "note": "2 in flat hot-joint gasket"
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  {
   "file": "heat-shield-2in",
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   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/heat-shield-2in.stl",
   "note": "2 in heat shield washer Ø89 × Ø50.8 bore (= tube OD): trace on sheet, slips over the tube between flame and clamp"
  },
  {
   "file": "clamp-half-2.5in",
   "formats": [
    "step",
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   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/clamp-half-2.5in.stl",
   "note": "2.5 in two-bolt clamp half (print two): 20° groove for the ISO 2852 rims, contact after 0.4 mm, 0.6 mm squeeze before the halves meet, 2 × M5 × 30 through Ø5.5 holes, nuts in 8 AF hex traps; 16.3 mm wide"
  },
  {
   "file": "hot-gasket-template-2.5in",
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   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-template-2.5in.stl",
   "note": "2.5 in flat hot-joint gasket"
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  {
   "file": "heat-shield-2.5in",
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   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
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   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/heat-shield-2.5in.stl",
   "note": "2.5 in heat shield washer Ø102.5 × Ø63.5 bore (= tube OD): trace on sheet, slips over the tube between flame and clamp"
  },
  {
   "file": "clamp-half-3in",
   "formats": [
    "step",
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   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/clamp-half-3in.stl",
   "note": "3 in two-bolt clamp half (print two): 20° groove for the ISO 2852 rims, contact after 0.4 mm, 0.6 mm squeeze before the halves meet, 2 × M5 × 30 through Ø5.5 holes, nuts in 8 AF hex traps; 16.5 mm wide"
  },
  {
   "file": "hot-gasket-template-3in",
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   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
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   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-template-3in.stl",
   "note": "3 in flat hot-joint gasket"
  },
  {
   "file": "heat-shield-3in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-clamps/heat-shield-3in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/heat-shield-3in.stl",
   "note": "3 in heat shield washer Ø116 × Ø76.2 bore (= tube OD): trace on sheet, slips over the tube between flame and clamp"
  },
  {
   "file": "clamp-half-4in",
   "formats": [
    "step",
    "stl"
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   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
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   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/clamp-half-4in.stl",
   "note": "4 in two-bolt clamp half (print two): 20° groove for the ISO 2852 rims, contact after 0.4 mm, 0.6 mm squeeze before the halves meet, 2 × M5 × 30 through Ø5.5 holes, nuts in 8 AF hex traps; 17.5 mm wide"
  },
  {
   "file": "hot-gasket-template-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-template-4in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/hot-gasket-template-4in.stl",
   "note": "4 in flat hot-joint gasket"
  },
  {
   "file": "heat-shield-4in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-clamps/heat-shield-4in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-clamps/heat-shield-4in.stl",
   "note": "4 in heat shield washer Ø144 × Ø101.6 bore (= tube OD): trace on sheet, slips over the tube between flame and clamp"
  }
 ],
 "markdown": "https://xemstudio.com/objects/tri-clamp-clamps/index.md"
}