{
 "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": "screw-jack-mechanism",
 "name": "Screw jack, Tr16×4 (4 mm lift per turn)",
 "kind": "hardware",
 "category": "Mechanisms",
 "group": "Screws",
 "year": null,
 "question": "How much force does a screw jack give?",
 "tags": [
  "mechanism",
  "screws",
  "kinematics",
  "507 mechanical movements"
 ],
 "aliases": [
  "screw jack",
  "jack screw",
  "lifting jack",
  "bottle jack screw",
  "gato de tornillo",
  "Schraubenwinde (Spindelheber)"
 ],
 "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/screw-jack-mechanism/",
 "sheet_txt": "https://xemstudio.com/objects/screw-jack-mechanism/sheet.txt",
 "sheet": {
  "basis": "Xem Studio design following Brown No. 389 (1868)",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Turning the screw in its threaded body lifts it one pitch per turn (4 mm). Ideal force gain = 2π × lever radius / pitch: 2π × 40 / 4 ≈ 63 with the 80 mm tommy bar; friction in the 30° thread takes about two-thirds of that and keeps the load from running back.",
   "Basic-profile Tr16×4 trapezoidal thread on screw and body, drawn engaged with no allowance.",
   "Brown's No. 389 (lifting jack).",
   "Parts (each has its own page): screw-jack-screw-tr16x4, screw-jack-body-tr16x4, tommy-bar-6x80.",
   "Brown's movement No. 389 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size."
  ],
  "table": {
   "columns": [
    "parameter",
    "value"
   ],
   "rows": [
    [
     "thread",
     "Tr16×4"
    ],
    [
     "lift per turn",
     "4 mm"
    ],
    [
     "lever radius",
     "40 mm"
    ],
    [
     "ideal gain",
     "≈ 63"
    ]
   ]
  }
 },
 "sheet_text": "Screw jack, Tr16×4 (4 mm lift per turn) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/screw-jack-mechanism/  (CC BY 4.0)\nBasis: Xem Studio design following Brown No. 389 (1868)\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Turning the screw in its threaded body lifts it one pitch per turn (4 mm). Ideal force gain = 2π × lever radius / pitch: 2π × 40 / 4 ≈ 63 with the 80 mm tommy bar; friction in the 30° thread takes about two-thirds of that and keeps the load from running back.\n- Basic-profile Tr16×4 trapezoidal thread on screw and body, drawn engaged with no allowance.\n- Brown's No. 389 (lifting jack).\n- Parts (each has its own page): screw-jack-screw-tr16x4, screw-jack-body-tr16x4, tommy-bar-6x80.\n- Brown's movement No. 389 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.\n\nparameter  value\nthread  Tr16×4\nlift per turn  4 mm\nlever radius  40 mm\nideal gain  ≈ 63\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. 389: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_389.html\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/screw-jack-mechanism/index.json\nAPI: https://xemstudio.com/api/geometry?object=screw-jack-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. 389: figure, his text and an animation",
   "url": "https://507movements.com/mm_389.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": [
  "screw-jack-screw-tr16x4",
  "screw-jack-body-tr16x4",
  "tommy-bar-6x80"
 ],
 "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 much force does a screw jack give?",
   "a": "Turning the screw in its threaded body lifts it one pitch per turn (4 mm). Ideal force gain = 2π × lever radius / pitch: 2π × 40 / 4 ≈ 63 with the 80 mm tommy bar; friction in the 30° thread takes about two-thirds of that and keeps the load from running back."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "screw-jack-mechanism-assembly",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/screw-jack-mechanism/screw-jack-mechanism-assembly.step",
   "stl": "https://xemstudio.com/files/hardware/screw-jack-mechanism/screw-jack-mechanism-assembly.stl",
   "note": "Assembled mechanism, all parts placed at one pose (STEP keeps each part separate)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/screw-jack-mechanism/index.md"
}