{
 "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-displacer",
 "name": "Mug LTD displacer Ø72 × 6",
 "kind": "hardware",
 "category": "Hardware",
 "group": "Stirling & thermoacoustic",
 "year": null,
 "question": "What size displacer for a mug-sized LTD Stirling engine?",
 "tags": [
  "ltd",
  "displacer",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "ltd stirling displacer size small",
  "mug stirling displacer"
 ],
 "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-displacer/",
 "sheet_txt": "https://xemstudio.com/objects/mug-ltd-displacer/sheet.txt",
 "sheet": {
  "basis": "2 mm radial gap to the Ø76 chamber like the LTD kit; swept volume at 15 mm stroke 61.1 mL",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Ø72 × 6 with a Ø2 bore for the rod (pressed through, flush at the bottom). Swept volume 61.1 mL against the 5 mL glass piston's 1.87 mL: ratio 33.",
   "2 mm radial gap to the chamber wall (designed); 1 mm end gaps at the ends of travel."
  ],
  "table": {
   "columns": [
    "feature",
    "value"
   ],
   "rows": [
    [
     "displacer",
     "Ø72 × 6"
    ],
    [
     "stroke",
     "15"
    ],
    [
     "swept volume",
     "61.1 mL"
    ],
    [
     "volume ratio",
     33
    ]
   ]
  }
 },
 "sheet_text": "Mug LTD displacer Ø72 × 6 — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/mug-ltd-displacer/  (CC BY 4.0)\nBasis: 2 mm radial gap to the Ø76 chamber like the LTD kit; swept volume at 15 mm stroke 61.1 mL\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Ø72 × 6 with a Ø2 bore for the rod (pressed through, flush at the bottom). Swept volume 61.1 mL against the 5 mL glass piston's 1.87 mL: ratio 33.\n- 2 mm radial gap to the chamber wall (designed); 1 mm end gaps at the ends of travel.\n\nfeature  value\ndisplacer  Ø72 × 6\nstroke  15\nswept volume  61.1 mL\nvolume ratio  33\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-displacer/index.json\nAPI: https://xemstudio.com/api/geometry?object=mug-ltd-displacer\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": "rod bore",
   "exact": "Ø2",
   "mates": "Ø2 displacer rod",
   "fit": "press",
   "files": "all"
  },
  {
   "feature": "outside",
   "exact": "Ø72 in a Ø76 bore",
   "mates": "chamber ring (2 radial gap)",
   "fit": "designed",
   "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 is the displacer to piston volume ratio of the mug LTD?",
   "a": "About 33: 61.1 mL displacer sweep to 1.87 mL of 5 mL glass syringe, both at 15 mm stroke."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "mug-ltd-displacer-72x6",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/mug-ltd-displacer/mug-ltd-displacer-72x6.step",
   "stl": "https://xemstudio.com/files/hardware/mug-ltd-displacer/mug-ltd-displacer-72x6.stl",
   "note": "displacer Ø72 × 6, Ø2 rod bore (2 mm radial gap to the Ø76 chamber: designed; 1 mm end gaps at the ends of its 15 mm stroke)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/mug-ltd-displacer/index.md"
}