{
 "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": "mug-ltd-chamber-ring",
 "name": "Mug LTD chamber ring Ø76 × 23",
 "kind": "hardware",
 "category": "Hardware",
 "group": "Stirling & thermoacoustic",
 "year": null,
 "question": "How tall should the chamber of a small LTD Stirling engine be?",
 "tags": [
  "ltd",
  "chamber",
  "ring",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "ltd stirling chamber ring",
  "mug stirling chamber"
 ],
 "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/mug-ltd-chamber-ring/",
 "sheet_txt": "https://xemstudio.com/objects/mug-ltd-chamber-ring/sheet.txt",
 "sheet": {
  "basis": "7 mm wall so the Ø5 syringe port at x 35 still opens into the chamber; 23 tall so a 6 mm displacer travels 15 with 1 mm at each end",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Ø76 bore, Ø90 outside (7 wall), 23 tall; 5 × Ø3.4 for the chamber screws on R41 and 2 × M3 tapped 2 deep in the top face at (35.5, ±20.5) for the crank pedestal's foot.",
   "Chamber 23 − displacer 6 = 17 free; the 15 mm stroke leaves 1 mm at the top and bottom of travel. 15 mm (7.5 throw) is the shortest stroke in the Ø3-bore crank discs whose con-rod eye (R4) clears a Ø3 shaft."
  ],
  "table": {
   "columns": [
    "feature",
    "size_mm"
   ],
   "rows": [
    [
     "bore × height",
     "76 × 23"
    ],
    [
     "outside",
     "Ø90"
    ],
    [
     "displacer gap",
     "2 radial, 1 at each end of stroke"
    ]
   ]
  }
 },
 "sheet_text": "Mug LTD chamber ring Ø76 × 23 — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/mug-ltd-chamber-ring/  (CC BY 4.0)\nBasis: 7 mm wall so the Ø5 syringe port at x 35 still opens into the chamber; 23 tall so a 6 mm displacer travels 15 with 1 mm at each end\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Ø76 bore, Ø90 outside (7 wall), 23 tall; 5 × Ø3.4 for the chamber screws on R41 and 2 × M3 tapped 2 deep in the top face at (35.5, ±20.5) for the crank pedestal's foot.\n- Chamber 23 − displacer 6 = 17 free; the 15 mm stroke leaves 1 mm at the top and bottom of travel. 15 mm (7.5 throw) is the shortest stroke in the Ø3-bore crank discs whose con-rod eye (R4) clears a Ø3 shaft.\n\nfeature  size_mm\nbore × height  76 × 23\noutside  Ø90\ndisplacer gap  2 radial, 1 at each end of stroke\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Atlanta Vinyl Store: Premium 11 oz sublimation mug: 3.75 in H × 3.25 in D — web — listing [verify license at link] — https://atlantavinylstore.com/products/premium-11oz-sublimation-mugs\n- James R. Senft: An Introduction to Low Temperature Differential Stirling Engines — book — Moriya Press [verify license at link] — https://www.stirlingengine.com/\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, 1 parts): https://xemstudio.com/files/hardware/mug-ltd-chamber-ring/index.json\nAPI: https://xemstudio.com/api/geometry?object=mug-ltd-chamber-ring\n",
 "sources": [
  {
   "publisher": "Atlanta Vinyl Store",
   "title": "Premium 11 oz sublimation mug: 3.75 in H × 3.25 in D",
   "url": "https://atlantavinylstore.com/products/premium-11oz-sublimation-mugs",
   "formats": [
    "web"
   ],
   "license": "listing",
   "license_verified": false,
   "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": "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": [
  "list-ltd-mug",
  "ltd-bottom-plate",
  "ltd-top-plate",
  "glass-syringes"
 ],
 "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": "bore",
   "exact": "Ø76",
   "mates": "displacer Ø72 (2 radial gap)",
   "fit": "designed",
   "files": "all"
  },
  {
   "feature": "screw holes",
   "exact": "Ø3.4, 5 on R41",
   "mates": "M3 clearance",
   "fit": "designed",
   "files": "all"
  },
  {
   "feature": "pedestal holes",
   "exact": "Ø2.5 × 2 deep (M3 tapped), at (35.5, ±20.5)",
   "mates": "shcs-m3x8 through the pedestal foot",
   "fit": "designed",
   "files": "all"
  },
  {
   "feature": "faces",
   "exact": "flat",
   "mates": "bottom and top plates (static seal)",
   "fit": "clamp",
   "files": "all"
  }
 ],
 "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 chamber height suits a 6 mm displacer with a 15 mm stroke?",
   "a": "23 mm: 17 free, 1 mm left at each end."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "mug-ltd-chamber-ring-76-h23",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/mug-ltd-chamber-ring/mug-ltd-chamber-ring-76-h23.step",
   "stl": "https://xemstudio.com/files/hardware/mug-ltd-chamber-ring/mug-ltd-chamber-ring-76-h23.stl",
   "note": "chamber ring Ø76 bore × 23, Ø90 outside (7 wall), 5 × Ø3.4 (M3 clearance) on R41, 2 × M3 tapped (Ø2.5) 2 deep in the top face at (35.5, ±20.5) for the crank pedestal"
  }
 ],
 "markdown": "https://xemstudio.com/objects/mug-ltd-chamber-ring/index.md"
}