{
 "version": "2026-10-20",
 "license": "Dimension sheets: CC BY 4.0. Standard and published-size files: CC BY 4.0. Xem Studio's own designs (files_license = Xem Studio Design License): free to use and sell things from, not to redistribute as files — https://xemstudio.com/license/. Other publishers' files: their own license, linked beside them.",
 "slug": "paradox-arm-25-25-b6",
 "name": "Train arm 64 × 14 × 5 with three Ø6 holes at 25 mm (Ferguson's paradox)",
 "kind": "modern",
 "category": "Hardware",
 "group": "Mechanism parts",
 "year": null,
 "question": "What is the arm of Ferguson's paradox?",
 "tags": [
  "mechanism part",
  "507 mechanical movements"
 ],
 "aliases": [
  "gear train arm",
  "planet arm",
  "brazo del tren",
  "Trägerarm"
 ],
 "overall_mm": {
  "length": 64,
  "width": 14,
  "height": 5
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": false,
 "free_files": 1,
 "url": "https://xemstudio.com/objects/paradox-arm-25-25-b6/",
 "sheet_txt": "https://xemstudio.com/objects/paradox-arm-25-25-b6/sheet.txt",
 "sheet": {
  "basis": "Xem Studio design following Brown's figure (1868); true size, no printing allowance",
  "overall_mm": {
   "length": 64,
   "width": 14,
   "height": 5
  },
  "notes": [
   "14 × 5 mm arm with Ø6 holes at 0, 25 and 50 mm: it turns on the fixed sun's Ø6 stud and carries the thick idler on the middle pin and the three paradox wheels on the end pin.",
   "Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features)."
  ],
  "table": {
   "columns": [
    "dimension",
    "value"
   ],
   "rows": [
    [
     "holes",
     "3 × Ø6 at 0 / 25 / 50 mm"
    ],
    [
     "section",
     "14 × 5 mm"
    ]
   ]
  }
 },
 "sheet_text": "Train arm 64 × 14 × 5 with three Ø6 holes at 25 mm (Ferguson's paradox) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/paradox-arm-25-25-b6/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)\nBasis: Xem Studio design following Brown's figure (1868); true size, no printing allowance\nCatalog version: 2026-10-20\n\nOverall (mm): length 64.0, width 14.0, height 5.0\n- 14 × 5 mm arm with Ø6 holes at 0, 25 and 50 mm: it turns on the fixed sun's Ø6 stud and carries the thick idler on the middle pin and the three paradox wheels on the end pin.\n- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).\n\ndimension  value\nholes  3 × Ø6 at 0 / 25 / 50 mm\nsection  14 × 5 mm\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Henry T. Brown (1868, public domain): Five Hundred and Seven Mechanical Movements — scan on archive.org — web — Publisher's page; dimensions are facts — https://archive.org/details/fivehundredseven00browiala\n- 507movements.com: Brown's movement No. 504: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_504.html\n- Xem Studio: drawing — web — Publisher's page; dimensions are facts — https://xemstudio.com/objects/fergusons-paradox-mechanism/\n\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/paradox-arm-25-25-b6/index.json\nAPI: https://xemstudio.com/api/geometry?object=paradox-arm-25-25-b6\n",
 "sources": [
  {
   "publisher": "Henry T. Brown (1868, public domain)",
   "title": "Five Hundred and Seven Mechanical Movements — scan on archive.org",
   "url": "https://archive.org/details/fivehundredseven00browiala",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "507movements.com",
   "title": "Brown's movement No. 504: figure, his text and an animation",
   "url": "https://507movements.com/mm_504.html",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Xem Studio",
   "title": "drawing",
   "url": "https://xemstudio.com/objects/fergusons-paradox-mechanism/",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "fergusons-paradox-mechanism"
 ],
 "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": [],
 "faq": [
  {
   "q": "What is the arm of Ferguson's paradox?",
   "a": "14 × 5 mm arm with Ø6 holes at 0, 25 and 50 mm: it turns on the fixed sun's Ø6 stud and carries the thick idler on the middle pin and the three paradox wheels on the end pin."
  }
 ],
 "files_license": {
  "name": "Xem Studio Design License",
  "holder": "Xem Studio",
  "url": "https://xemstudio.com/license/",
  "note": "Xem Studio's own design: free to use, print, modify and sell things made from it; not to be republished or redistributed as files."
 },
 "offers": [
  {
   "file": "paradox-arm-25-25-b6",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/paradox-arm-25-25-b6/paradox-arm-25-25-b6.step",
   "stl": "https://xemstudio.com/files/hardware/paradox-arm-25-25-b6/paradox-arm-25-25-b6.stl",
   "note": "arm, z 0..5, stud hole at the origin"
  }
 ],
 "markdown": "https://xemstudio.com/objects/paradox-arm-25-25-b6/index.md"
}