{
 "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-crank-pedestal",
 "name": "Mug LTD crank pedestal (one bearing block, two 623s)",
 "kind": "hardware",
 "category": "Hardware",
 "group": "Stirling & thermoacoustic",
 "year": null,
 "question": "What holds the crankshaft above a small LTD Stirling engine?",
 "tags": [
  "ltd",
  "crank",
  "pedestal",
  "623",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "ltd stirling crank support",
  "mug stirling crank pedestal"
 ],
 "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-crank-pedestal/",
 "sheet_txt": "https://xemstudio.com/objects/mug-ltd-crank-pedestal/sheet.txt",
 "sheet": {
  "basis": "My geometry: crank axis 169 above the top plate, set by the 5 mL glass syringe (105 long) plus clevis and 45 mm con-rod; both cranks overhung, one each side of the block",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Both cranks are overhung: the flywheel crank on the displacer side and a crank disc on the syringe side, with a Ø3 × 30 shaft in two 623s in one 10 mm bearing block between them. No con-rod crosses the shaft, so nothing in the mechanism meets it at top dead centre.",
   "The post stands beside the syringe (y −27..−13) so the plunger clevis and barrel collar pass it; the foot's two arms reach round the syringe socket boss to two M3 × 8 at (35.5, ±20.5), through the top plate into tapped holes in the ring.",
   "The crank height comes from the glass syringe: its 105 mm barrel stands in the top plate, the plunger clevis pin is 12 above the plunger collar, and the con-rod is 45."
  ],
  "table": {
   "columns": [
    "feature",
    "value_mm"
   ],
   "rows": [
    [
     "crank axis above top plate",
     169
    ],
    [
     "bearing block",
     "x 15.5..25.5"
    ],
    [
     "bearings",
     "2 × 623"
    ]
   ]
  }
 },
 "sheet_text": "Mug LTD crank pedestal (one bearing block, two 623s) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/mug-ltd-crank-pedestal/  (CC BY 4.0)\nBasis: My geometry: crank axis 169 above the top plate, set by the 5 mL glass syringe (105 long) plus clevis and 45 mm con-rod; both cranks overhung, one each side of the block\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Both cranks are overhung: the flywheel crank on the displacer side and a crank disc on the syringe side, with a Ø3 × 30 shaft in two 623s in one 10 mm bearing block between them. No con-rod crosses the shaft, so nothing in the mechanism meets it at top dead centre.\n- The post stands beside the syringe (y −27..−13) so the plunger clevis and barrel collar pass it; the foot's two arms reach round the syringe socket boss to two M3 × 8 at (35.5, ±20.5), through the top plate into tapped holes in the ring.\n- The crank height comes from the glass syringe: its 105 mm barrel stands in the top plate, the plunger clevis pin is 12 above the plunger collar, and the con-rod is 45.\n\nfeature  value_mm\ncrank axis above top plate  169.0\nbearing block  x 15.5..25.5\nbearings  2 × 623\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\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-crank-pedestal/index.json\nAPI: https://xemstudio.com/api/geometry?object=mug-ltd-crank-pedestal\n",
 "sources": [
  {
   "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": "bearing pockets",
   "exact": "Ø10 × 4, one in each face of the block",
   "mates": "623 bearing OD 10",
   "fit": "press",
   "files": "all"
  },
  {
   "feature": "shaft clearance",
   "exact": "Ø5",
   "mates": "Ø3 shaft (no contact)",
   "fit": "designed",
   "files": "all"
  },
  {
   "feature": "foot holes",
   "exact": "Ø3.4",
   "mates": "M3 clearance",
   "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": "Why is the mug LTD so tall?",
   "a": "The glass syringe is 105 mm long and stands upright in the top plate; the crank sits a con-rod length above its plunger."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "mug-ltd-crank-pedestal",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/mug-ltd-crank-pedestal/mug-ltd-crank-pedestal.step",
   "stl": "https://xemstudio.com/files/hardware/mug-ltd-crank-pedestal/mug-ltd-crank-pedestal.stl",
   "note": "crank pedestal: foot with two arms round the syringe boss (to x 38.5) with 2 × Ø3.4, post 10 × 14 beside the syringe, bearing block 10 thick at x 15.5..25.5 with a 623 pocket (Ø10 × 4) in each face and Ø5 between, axis 169 above the top plate"
  }
 ],
 "markdown": "https://xemstudio.com/objects/mug-ltd-crank-pedestal/index.md"
}