{
 "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-engine-base-plate",
 "name": "Base plate for 1.5, 2 and 3 in tri-clamp Stirling engines",
 "kind": "hardware",
 "category": "Stirling engines",
 "group": "Drives & mechanisms",
 "year": null,
 "question": "What base plate mounts a tri-clamp Stirling engine and its crank?",
 "tags": [
  "base plate",
  "frame",
  "gamma",
  "tri-clamp",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "stirling engine base plate",
  "tri clamp engine mount",
  "tri clamp stirling base"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 3,
 "url": "https://xemstudio.com/objects/tri-clamp-engine-base-plate/",
 "sheet_txt": "https://xemstudio.com/objects/tri-clamp-engine-base-plate/sheet.txt",
 "sheet": {
  "basis": "Spool passage = ISO 2852 flange Ø + 2 (50.5 / 64 / 91); width flange + 90, depth max(70, flange + 30); M5 clearance Ø5.5 (ISO 273 medium)",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "A 6 mm plate with 6 mm corner radii, sized to the tri-clamp flange: 140.5 × 80.5 (1.5 in), 154 × 94 (2 in), 181 × 121 (3 in).",
   "On centre a passage Ø52.5 / Ø66 / Ø93 (flange Ø + 2) that the spool or its cap goes through without contact.",
   "Either side, a 16 × 3.4 slot at flange radius + 18 for the crank stands' M3 screws; at the ends, 4 × Ø5.5 holes (50 mm apart across, 12 in from each end) for M5 into 2020 extrusion."
  ],
  "table": {
   "columns": [
    "file",
    "plate",
    "spool passage",
    "stand slots at",
    "M5 holes"
   ],
   "rows": [
    [
     "base-plate-1.5in",
     "140.5 × 80.5 × 6",
     52.5,
     "±43.25",
     "4 × Ø5.5, 116.5 × 50"
    ],
    [
     "base-plate-2in",
     "154 × 94 × 6",
     66,
     "±50",
     "4 × Ø5.5, 130 × 50"
    ],
    [
     "base-plate-3in",
     "181 × 121 × 6",
     93,
     "±63.5",
     "4 × Ø5.5, 157 × 50"
    ]
   ]
  }
 },
 "sheet_text": "Base plate for 1.5, 2 and 3 in tri-clamp Stirling engines — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/tri-clamp-engine-base-plate/  (CC BY 4.0)\nBasis: Spool passage = ISO 2852 flange Ø + 2 (50.5 / 64 / 91); width flange + 90, depth max(70, flange + 30); M5 clearance Ø5.5 (ISO 273 medium)\nCatalog version: 2026-10-20\n\nSizes: see table below\n- A 6 mm plate with 6 mm corner radii, sized to the tri-clamp flange: 140.5 × 80.5 (1.5 in), 154 × 94 (2 in), 181 × 121 (3 in).\n- On centre a passage Ø52.5 / Ø66 / Ø93 (flange Ø + 2) that the spool or its cap goes through without contact.\n- Either side, a 16 × 3.4 slot at flange radius + 18 for the crank stands' M3 screws; at the ends, 4 × Ø5.5 holes (50 mm apart across, 12 in from each end) for M5 into 2020 extrusion.\n\nfile  plate  spool passage  stand slots at  M5 holes\nbase-plate-1.5in  140.5 × 80.5 × 6  52.5  ±43.25  4 × Ø5.5, 116.5 × 50\nbase-plate-2in  154 × 94 × 6  66  ±50  4 × Ø5.5, 130 × 50\nbase-plate-3in  181 × 121 × 6  93  ±63.5  4 × Ø5.5, 157 × 50\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Wikipedia: Beam engine — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Beam_engine\n- Wikipedia: Stirling engine — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Stirling_engine\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, 3 parts): https://xemstudio.com/files/hardware/tri-clamp-engine-base-plate/index.json\nAPI: https://xemstudio.com/api/geometry?object=tri-clamp-engine-base-plate\n",
 "sources": [
  {
   "publisher": "Wikipedia",
   "title": "Beam engine",
   "url": "https://en.wikipedia.org/wiki/Beam_engine",
   "formats": [
    "web"
   ],
   "license": "CC BY-SA 4.0 (text)",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Wikipedia",
   "title": "Stirling engine",
   "url": "https://en.wikipedia.org/wiki/Stirling_engine",
   "formats": [
    "web"
   ],
   "license": "CC BY-SA 4.0 (text)",
   "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": [
  "rod-clevises",
  "power-cylinder-liner",
  "tri-clamp-spool",
  "t-slot-extrusions",
  "rocker-beam",
  "list-gamma-2in-tri-clamp"
 ],
 "fits": [
  {
   "role": "Parts that fit it",
   "items": [
    {
     "slug": "crosshead-guide-8mm",
     "why": "flanged to the frame in line with the liner"
    },
    {
     "slug": "beam-pivot-post",
     "why": "2 × M3 to the base"
    },
    {
     "slug": "crank-stands-625",
     "why": "M3 through the foot slots into the plate slots"
    }
   ]
  },
  {
   "role": "Goes in or on",
   "items": [
    {
     "slug": "t-slot-extrusions",
     "why": "4 × M5 into 2020"
    }
   ]
  },
  {
   "role": "Connects to",
   "items": [
    {
     "slug": "tri-clamp-spool",
     "why": "spool through the passage"
    },
    {
     "slug": "rod-clevises",
     "why": "625 crank stands in the slots"
    },
    {
     "slug": "power-cylinder-liner",
     "why": "liner flange on the plate"
    }
   ]
  },
  {
   "role": "Also needed",
   "items": [
    {
     "slug": "slide-in-t-nuts",
     "why": "T-nuts"
    }
   ]
  }
 ],
 "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": "base-plate spool passage",
   "exact": "flange Ø + 2",
   "mates": "ferrule flange passes through",
   "fit": "designed",
   "files": "base-plate-"
  },
  {
   "feature": "base-plate M5 holes",
   "exact": "Ø5.5",
   "mates": "M5 screw clearance (ISO 273 medium)",
   "fit": "designed",
   "files": "base-plate-"
  },
  {
   "feature": "crank-stand slots",
   "exact": "3.4 × 16, 2 per stand at y ±21 (42 apart), x ±(flange/2 + 16)",
   "mates": "crank-stand-625 foot slots, M3 screws",
   "fit": "designed",
   "files": "base-plate-"
  }
 ],
 "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 tri-clamp Stirling engine?",
   "a": "On the base plate: spool through the Ø66 passage (2 in), crank stands in the slots, 4 × M5 down into 2020 or a board."
  },
  {
   "q": "What size is the 2 in base plate?",
   "a": "154 × 94 × 6 with a Ø66 passage."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "base-plate-1.5in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/gamma-base-plate-and-beam/base-plate-1.5in.step",
   "stl": "https://xemstudio.com/files/hardware/gamma-base-plate-and-beam/base-plate-1.5in.stl",
   "note": "base plate for a 1.5 in tri-clamp engine, 140.5 × 80.5 × 6: Ø52.5 spool passage (flange Ø + 2), two crank-stand-625 seats at x ±41.25, each 2 × M3 slots 3.4 × 16 (along y) on y ±21 (the stand's 42 mm foot pitch), 4 × M5 clearance (Ø5.5) at x ±58.25, y ±25 to 2020 extrusion"
  },
  {
   "file": "base-plate-2in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/gamma-base-plate-and-beam/base-plate-2in.step",
   "stl": "https://xemstudio.com/files/hardware/gamma-base-plate-and-beam/base-plate-2in.stl",
   "note": "base plate for a 2 in tri-clamp engine, 154 × 94 × 6: Ø66 spool passage (flange Ø + 2), two crank-stand-625 seats at x ±48, each 2 × M3 slots 3.4 × 16 (along y) on y ±21 (the stand's 42 mm foot pitch), 4 × M5 clearance (Ø5.5) at x ±65, y ±25 to 2020 extrusion"
  },
  {
   "file": "base-plate-3in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/gamma-base-plate-and-beam/base-plate-3in.step",
   "stl": "https://xemstudio.com/files/hardware/gamma-base-plate-and-beam/base-plate-3in.stl",
   "note": "base plate for a 3 in tri-clamp engine, 181 × 121 × 6: Ø93 spool passage (flange Ø + 2), two crank-stand-625 seats at x ±61.5, each 2 × M3 slots 3.4 × 16 (along y) on y ±21 (the stand's 42 mm foot pitch), 4 × M5 clearance (Ø5.5) at x ±78.5, y ±25 to 2020 extrusion"
  }
 ],
 "markdown": "https://xemstudio.com/objects/tri-clamp-engine-base-plate/index.md"
}