{
 "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-bearing-cap",
 "name": "Tri-clamp bearing cap: 2 in cap with a long Ø3 shaft bore and two 623 seats",
 "kind": "hardware",
 "category": "Hardware",
 "group": "Stirling & thermoacoustic",
 "year": null,
 "question": "How do I bring a crankshaft out of a sealed tri-clamp crankcase?",
 "tags": [
  "bearing cap",
  "shaft seal",
  "crankcase",
  "cap",
  "623",
  "tri-clamp",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "tri clamp bearing cap",
  "crankshaft through tri clamp cap",
  "sealed crankcase shaft",
  "clearance seal crankshaft",
  "stirling crankcase cap"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 1,
 "url": "https://xemstudio.com/objects/tri-clamp-bearing-cap/",
 "sheet_txt": "https://xemstudio.com/objects/tri-clamp-bearing-cap/sheet.txt",
 "sheet": {
  "basis": "ISO 2852 clamp face and 20° back exactly as the flat end cap on this site (gen_hardware.tc_cap); 623 bearing 3 × 10 × 4 (ISO 15); bore length and spigot are design values",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "A cap for a 2 in ferrule face that lets a thin crankshaft out of a crankcase that holds working gas. The face, the 1.6 mm recess and the 20° back cone are the flat end cap's, so the standard clamp and Type B gasket close it like any cap.",
   "On the gas side a Ø16 spigot runs 77.1 mm in from the face: through the gasket lip and through the Ø16 bore of the branch plug to the crank chamber. A 623 seat (Ø10 × 4) at the spigot end carries the shaft next to the crank; a second 623 seat in the back carries it next to the flywheel.",
   "Between the two seats the shaft runs in a Ø3 bore 75.1 mm long. That close running fit is the only way out for the gas: no seal, no O-ring, so almost no friction.",
   "Fits: Ø3 bore run on the Ø3 shaft; seats press on the 623 outer ring; spigot slide in the plug bore; the face is a clamp face."
  ],
  "table": {
   "columns": [
    "feature",
    "value"
   ],
   "rows": [
    [
     "face",
     "ISO 2852, 2 in (Ø64 flange)"
    ],
    [
     "flat back",
     "Ø46.7 at 6"
    ],
    [
     "spigot",
     "Ø16 × 77.1 from the face"
    ],
    [
     "bearing seats",
     "2 × Ø10 × 4 (623)"
    ],
    [
     "shaft bore",
     "Ø3 × 75.1 (run)"
    ]
   ]
  }
 },
 "sheet_text": "Tri-clamp bearing cap: 2 in cap with a long Ø3 shaft bore and two 623 seats — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/tri-clamp-bearing-cap/  (CC BY 4.0)\nBasis: ISO 2852 clamp face and 20° back exactly as the flat end cap on this site (gen_hardware.tc_cap); 623 bearing 3 × 10 × 4 (ISO 15); bore length and spigot are design values\nCatalog version: 2026-10-20\n\nSizes: see table below\n- A cap for a 2 in ferrule face that lets a thin crankshaft out of a crankcase that holds working gas. The face, the 1.6 mm recess and the 20° back cone are the flat end cap's, so the standard clamp and Type B gasket close it like any cap.\n- On the gas side a Ø16 spigot runs 77.1 mm in from the face: through the gasket lip and through the Ø16 bore of the branch plug to the crank chamber. A 623 seat (Ø10 × 4) at the spigot end carries the shaft next to the crank; a second 623 seat in the back carries it next to the flywheel.\n- Between the two seats the shaft runs in a Ø3 bore 75.1 mm long. That close running fit is the only way out for the gas: no seal, no O-ring, so almost no friction.\n- Fits: Ø3 bore run on the Ø3 shaft; seats press on the 623 outer ring; spigot slide in the plug bore; the face is a clamp face.\n\nfeature  value\nface  ISO 2852, 2 in (Ø64 flange)\nflat back  Ø46.7 at 6\nspigot  Ø16 × 77.1 from the face\nbearing seats  2 × Ø10 × 4 (623)\nshaft bore  Ø3 × 75.1 (run)\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\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- 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- Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/tri-clamp-bearing-cap/index.json\nAPI: https://xemstudio.com/api/geometry?object=tri-clamp-bearing-cap\n",
 "sources": [
  {
   "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": "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": "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-end-cap",
  "tri-clamp-cross-branch-plug",
  "tri-clamp-cross-crank-webs",
  "ball-bearings-metric",
  "metric-shafts",
  "list-tri-clamp-cross-diaphragm-gamma"
 ],
 "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": "cap face",
   "exact": "ISO 2852 (land Ø56.5–Ø64, rim 2.85, 1.6 recess, 20° back to the flat back)",
   "mates": "standard clamp + Type B gasket",
   "fit": "clamp",
   "files": "bearing-cap-"
  },
  {
   "feature": "shaft bore",
   "exact": "Ø3 × 75.1 between the seats",
   "mates": "Ø3 crankshaft (shaft-3x100): the clearance seal, the only leak path",
   "fit": "run",
   "files": "bearing-cap-"
  },
  {
   "feature": "bearing seats",
   "exact": "2 × Ø10 × 4 (back and spigot end)",
   "mates": "623 outer ring",
   "fit": "press",
   "files": "bearing-cap-"
  },
  {
   "feature": "spigot",
   "exact": "Ø16 × 77.1 from the face",
   "mates": "Ø16 bore of branch-plug-2in-bore16",
   "fit": "slide",
   "files": "bearing-cap-"
  }
 ],
 "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 does the shaft get out without a seal?",
   "a": "Through a Ø3 bore 75.1 mm long between two 623 seats: a long close running fit leaks very little and adds almost no friction."
  },
  {
   "q": "Does it fit a standard clamp and gasket?",
   "a": "Yes: the face and back are the flat end cap's ISO 2852 profile."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "bearing-cap-2in-b3",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-bearing-cap/bearing-cap-2in-b3.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-bearing-cap/bearing-cap-2in-b3.stl",
   "note": "2 in bearing cap: ISO 2852 face (land Ø56.5–Ø64, rim 2.85, recess 1.6 inside Ø56.5), 20° back to the 6 mm flat back (Ø46.7) as the flat end cap; Ø16 spigot 77.1 from the face; 623 seats Ø10 × 4 in the back and at the spigot end; Ø3 bore 75.1 long between them"
  }
 ],
 "markdown": "https://xemstudio.com/objects/tri-clamp-bearing-cap/index.md"
}