{
 "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": "scott-russell-straight-line-mechanism",
 "name": "Scott Russell straight-line linkage (half-scissor)",
 "kind": "hardware",
 "category": "Mechanisms",
 "group": "Linkages",
 "year": null,
 "question": "How does the Scott Russell linkage make a straight line?",
 "tags": [
  "mechanism",
  "linkages",
  "kinematics",
  "507 mechanical movements"
 ],
 "aliases": [
  "scott russell linkage",
  "scott russell mechanism",
  "exact straight line linkage",
  "mecanismo de Scott Russell",
  "Scott-Russell-Geradführung"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": false,
 "free_files": 1,
 "url": "https://xemstudio.com/objects/scott-russell-straight-line-mechanism/",
 "sheet_txt": "https://xemstudio.com/objects/scott-russell-straight-line-mechanism/sheet.txt",
 "sheet": {
  "basis": "Xem Studio design following Brown No. 339 (1868)",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "A bar AB of length 2r has its midpoint C pinned to a radius link OC = r; end A slides on a straight guide through O. Because A, B and O always lie on a circle round C, B moves on the exact straight line through O at right angles to the guide.",
   "Here r = 40: bar 80 mm (centre-hole link), radius link 40 mm, A in a 6.2 mm slot; at 35° B is 45.89 mm up the perpendicular. A moves 80·cos φ, B 80·sin φ.",
   "Brown's No. 339 (bar on the rod, one end sliding in a fixed slot, radius bar to its middle).",
   "Parts (each has its own page): centre-hole-link-80, four-bar-links, slot-guide-plate-90, slide-block-12x6, dowel-pins-metric.",
   "Brown's movement No. 339 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size."
  ],
  "table": {
   "columns": [
    "parameter",
    "value"
   ],
   "rows": [
    [
     "bar AB",
     "80 mm"
    ],
    [
     "radius OC",
     "40 mm"
    ],
    [
     "guide",
     "6.2 mm slot"
    ],
    [
     "path of B",
     "exact straight line"
    ]
   ]
  }
 },
 "sheet_text": "Scott Russell straight-line linkage (half-scissor) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/scott-russell-straight-line-mechanism/  (CC BY 4.0)\nBasis: Xem Studio design following Brown No. 339 (1868)\nCatalog version: 2026-10-20\n\nSizes: see table below\n- A bar AB of length 2r has its midpoint C pinned to a radius link OC = r; end A slides on a straight guide through O. Because A, B and O always lie on a circle round C, B moves on the exact straight line through O at right angles to the guide.\n- Here r = 40: bar 80 mm (centre-hole link), radius link 40 mm, A in a 6.2 mm slot; at 35° B is 45.89 mm up the perpendicular. A moves 80·cos φ, B 80·sin φ.\n- Brown's No. 339 (bar on the rod, one end sliding in a fixed slot, radius bar to its middle).\n- Parts (each has its own page): centre-hole-link-80, four-bar-links, slot-guide-plate-90, slide-block-12x6, dowel-pins-metric.\n- Brown's movement No. 339 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.\n\nparameter  value\nbar AB  80 mm\nradius OC  40 mm\nguide  6.2 mm slot\npath of B  exact straight line\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. 339: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_339.html\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/scott-russell-straight-line-mechanism/index.json\nAPI: https://xemstudio.com/api/geometry?object=scott-russell-straight-line-mechanism\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. 339: figure, his text and an animation",
   "url": "https://507movements.com/mm_339.html",
   "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": [
  "centre-hole-link-80",
  "four-bar-links",
  "slot-guide-plate-90",
  "slide-block-12x6",
  "dowel-pins-metric"
 ],
 "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": "How does the Scott Russell linkage make a straight line?",
   "a": "A bar AB of length 2r has its midpoint C pinned to a radius link OC = r; end A slides on a straight guide through O. Because A, B and O always lie on a circle round C, B moves on the exact straight line through O at right angles to the guide."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "scott-russell-straight-line-mechanism-assembly",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/scott-russell-straight-line-mechanism/scott-russell-straight-line-mechanism-assembly.step",
   "stl": "https://xemstudio.com/files/hardware/scott-russell-straight-line-mechanism/scott-russell-straight-line-mechanism-assembly.stl",
   "note": "Assembled mechanism, all parts placed at one pose (STEP keeps each part separate)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/scott-russell-straight-line-mechanism/index.md"
}