{
 "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": "threaded-rods-metric",
 "name": "Threaded rod, metric: M4 × 194.2",
 "kind": "hardware",
 "category": "Stirling engines",
 "group": "Drives & mechanisms",
 "year": null,
 "question": "How long a rod carries the flexures of the 2 in free-piston mover?",
 "tags": [
  "threaded rod",
  "rod",
  "m4",
  "tri-clamp",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "m4 threaded rod length",
  "flexure rod free piston"
 ],
 "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/threaded-rods-metric/",
 "sheet_txt": "https://xemstudio.com/objects/threaded-rods-metric/sheet.txt",
 "sheet": {
  "basis": "ISO metric M4; thread drawn as the plain major diameter, this site's convention",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "M4 threaded rod cut to 195.9: from the mover crown's tapped hole down through both flexure stacks to 1 mm below the last hub nut."
  ],
  "table": {
   "columns": [
    "thread",
    "length_mm"
   ],
   "rows": [
    [
     "M4",
     195.9
    ]
   ]
  }
 },
 "sheet_text": "Threaded rod, metric: M4 × 194.2 — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/threaded-rods-metric/  (CC BY 4.0)\nBasis: ISO metric M4; thread drawn as the plain major diameter, this site's convention\nCatalog version: 2026-10-20\n\nSizes: see table below\n- M4 threaded rod cut to 195.9: from the mover crown's tapped hole down through both flexure stacks to 1 mm below the last hub nut.\n\nthread  length_mm\nM4  195.9\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Xem Studio: tools/gen_ta_power.py: the network model and every dimension on this page — code — CC BY 4.0 — https://xemstudio.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, 1 parts): https://xemstudio.com/files/hardware/threaded-rods-metric/index.json\nAPI: https://xemstudio.com/api/geometry?object=threaded-rods-metric\n",
 "sources": [
  {
   "publisher": "Xem Studio",
   "title": "tools/gen_ta_power.py: the network model and every dimension on this page",
   "url": "https://xemstudio.com/",
   "formats": [
    "code"
   ],
   "license": "CC BY 4.0",
   "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": [
  "stirling-crankshafts",
  "hex-nuts-metric",
  "tri-clamp-flexure-carrier"
 ],
 "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": "thread",
   "exact": "M4 (drawn Ø4)",
   "mates": "mover crown tap drill, hub nuts",
   "fit": "designed",
   "files": "all"
  },
  {
   "feature": "rod through the hubs",
   "exact": "Ø4",
   "mates": "flexure hub Ø4, hub washer Ø4",
   "fit": "slide",
   "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 threaded?",
   "a": "The leaf hubs are clamped between nuts anywhere along it; no shoulders to machine."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "rod-m4x195.9",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/threaded-rods-metric/rod-m4x195.9.step",
   "stl": "https://xemstudio.com/files/hardware/threaded-rods-metric/rod-m4x195.9.stl",
   "note": "M4 threaded rod × 195.9, thread as a plain Ø4 cylinder"
  }
 ],
 "markdown": "https://xemstudio.com/objects/threaded-rods-metric/index.md"
}