{
 "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": "ltd-chamber-ring",
 "name": "LTD Stirling chamber ring, Ø100 and Ø150 × 20",
 "kind": "hardware",
 "category": "Stirling engines",
 "group": "Can & LTD engines",
 "year": null,
 "question": "What size is the chamber ring of a coffee-cup Stirling engine?",
 "tags": [
  "ltd",
  "chamber",
  "ring",
  "coffee cup",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "ltd stirling chamber ring",
  "coffee cup stirling cylinder",
  "ltd displacer chamber size",
  "low temperature stirling ring stl"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 2,
 "url": "https://xemstudio.com/objects/ltd-chamber-ring/",
 "sheet_txt": "https://xemstudio.com/objects/ltd-chamber-ring/sheet.txt",
 "sheet": {
  "basis": "Chamber height 20: an 8 mm displacer at 10 mm stroke (crank-disc-b3-stroke10) with 1 mm at each end; M3 tap drill Ø2.5",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "The wall of the LTD displacer chamber, between the bottom and top plates. Bore Ø100 or Ø150, 20 tall, 10 mm wall (outside Ø120 / Ø170).",
   "Six Ø2.5 holes (M3 tap drill) through its height on a Ø112 / Ø162 circle: an M3 × 12 comes in from each plate.",
   "The displacer runs inside with a 2 mm radial gap by design; nothing moving touches the ring."
  ],
  "table": {
   "columns": [
    "file",
    "bore",
    "outside",
    "height",
    "screw circle"
   ],
   "rows": [
    [
     "ltd-100-chamber-ring-h20",
     100,
     120,
     20,
     112
    ],
    [
     "ltd-150-chamber-ring-h20",
     150,
     170,
     20,
     162
    ]
   ]
  }
 },
 "sheet_text": "LTD Stirling chamber ring, Ø100 and Ø150 × 20 — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/ltd-chamber-ring/  (CC BY 4.0)\nBasis: Chamber height 20: an 8 mm displacer at 10 mm stroke (crank-disc-b3-stroke10) with 1 mm at each end; M3 tap drill Ø2.5\nCatalog version: 2026-10-20\n\nSizes: see table below\n- The wall of the LTD displacer chamber, between the bottom and top plates. Bore Ø100 or Ø150, 20 tall, 10 mm wall (outside Ø120 / Ø170).\n- Six Ø2.5 holes (M3 tap drill) through its height on a Ø112 / Ø162 circle: an M3 × 12 comes in from each plate.\n- The displacer runs inside with a 2 mm radial gap by design; nothing moving touches the ring.\n\nfile  bore  outside  height  screw circle\nltd-100-chamber-ring-h20  100  120  20  112\nltd-150-chamber-ring-h20  150  170  20  162\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Wikipedia: Stirling engine — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Stirling_engine\n- James R. Senft: An Introduction to Low Temperature Differential Stirling Engines — book — Moriya Press [verify license at link] — https://www.stirlingengine.com/\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, 2 parts): https://xemstudio.com/files/hardware/ltd-chamber-ring/index.json\nAPI: https://xemstudio.com/api/geometry?object=ltd-chamber-ring\n",
 "sources": [
  {
   "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": "James R. Senft",
   "title": "An Introduction to Low Temperature Differential Stirling Engines",
   "url": "https://www.stirlingengine.com/",
   "formats": [
    "book"
   ],
   "license": "Moriya Press",
   "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": [
  "ltd-top-plate",
  "ltd-bottom-plate",
  "ltd-displacer",
  "list-ltd-coffee-cup"
 ],
 "fits": [
  {
   "role": "Connects to",
   "items": [
    {
     "slug": "ltd-top-plate",
     "why": "top face, 6 × M3"
    },
    {
     "slug": "ltd-bottom-plate",
     "why": "bottom face, 6 × M3"
    },
    {
     "slug": "ltd-displacer",
     "why": "displacer inside, 2 mm radial gap"
    }
   ]
  }
 ],
 "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": "chamber-ring screw holes",
   "exact": "Ø2.5 through",
   "mates": "M3 tap drill (an M3 × 12 from each plate)",
   "fit": "designed",
   "files": "ltd-100-chamber"
  },
  {
   "feature": "chamber-ring screw holes",
   "exact": "Ø2.5 through",
   "mates": "M3 tap drill (an M3 × 12 from each plate)",
   "fit": "designed",
   "files": "ltd-150-chamber"
  }
 ],
 "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 tall is the chamber of the LTD Stirling engine here?",
   "a": "20 mm, for an 8 mm thick displacer moving 10 mm: 1 mm to spare at each end."
  },
  {
   "q": "What displacer goes in the Ø100 chamber ring?",
   "a": "The Ø96 × 8 LTD displacer: 2 mm radial gap, designed."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "ltd-100-chamber-ring-h20",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/ltd-coffee-cup-engine-kit/ltd-100-chamber-ring-h20.step",
   "stl": "https://xemstudio.com/files/hardware/ltd-coffee-cup-engine-kit/ltd-100-chamber-ring-h20.stl",
   "note": "chamber ring Ø100 bore × 20 tall, 10 mm wall, 6 × Ø2.5 (M3 tapped) through on a Ø112 circle; the displacer runs inside"
  },
  {
   "file": "ltd-150-chamber-ring-h20",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/ltd-coffee-cup-engine-kit/ltd-150-chamber-ring-h20.step",
   "stl": "https://xemstudio.com/files/hardware/ltd-coffee-cup-engine-kit/ltd-150-chamber-ring-h20.stl",
   "note": "chamber ring Ø150 bore × 20 tall, 10 mm wall, 6 × Ø2.5 (M3 tapped) through on a Ø162 circle; the displacer runs inside"
  }
 ],
 "markdown": "https://xemstudio.com/objects/ltd-chamber-ring/index.md"
}