{
 "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": "crossed-helical-gears-mechanism",
 "name": "Crossed helical (spiral) gears on shafts at 90°, 16 : 16",
 "kind": "hardware",
 "category": "Mechanisms",
 "group": "Gears",
 "year": null,
 "question": "How do crossed helical gears connect shafts that do not meet?",
 "tags": [
  "mechanism",
  "gears",
  "kinematics",
  "507 mechanical movements"
 ],
 "aliases": [
  "crossed helical gears",
  "spiral gears",
  "skew gears",
  "screw gears",
  "engranajes helicoidales cruzados",
  "Schraubradgetriebe"
 ],
 "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/crossed-helical-gears-mechanism/",
 "sheet_txt": "https://xemstudio.com/objects/crossed-helical-gears-mechanism/sheet.txt",
 "sheet": {
  "basis": "Xem Studio design following Brown No. 43 (1868)",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Two helical gears of the same hand on shafts that cross without meeting: the shaft angle equals the sum of the helix angles (45° + 45° = 90° here). The teeth touch at a point and slide along each other, so they suit light loads — instrument drives, distributor and oil-pump drives.",
   "Normal module 1.5, 16 teeth, 45° right hand on both: pitch Ø33.94 each (m_n·N / cos β), shafts 33.94 mm apart; ratio 1 : 1 (N₂/N₁, not the diameters). The second gear's phase was found by search to the touching position.",
   "Brown's No. 43 (gears transmitting rotary motion between shafts arranged obliquely, another form).",
   "Parts (each has its own page): crossed-helical-gear-mn1-5-16t-beta45-rh-bore6, linear-shafts-h6.",
   "Brown's movement No. 43 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size."
  ],
  "table": {
   "columns": [
    "parameter",
    "value"
   ],
   "rows": [
    [
     "normal module",
     "1.5"
    ],
    [
     "teeth",
     "16 / 16"
    ],
    [
     "helix",
     "45° RH both"
    ],
    [
     "shaft angle",
     "90°, offset"
    ],
    [
     "centre distance",
     "33.94 mm"
    ]
   ]
  }
 },
 "sheet_text": "Crossed helical (spiral) gears on shafts at 90°, 16 : 16 — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/crossed-helical-gears-mechanism/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)\nBasis: Xem Studio design following Brown No. 43 (1868)\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Two helical gears of the same hand on shafts that cross without meeting: the shaft angle equals the sum of the helix angles (45° + 45° = 90° here). The teeth touch at a point and slide along each other, so they suit light loads — instrument drives, distributor and oil-pump drives.\n- Normal module 1.5, 16 teeth, 45° right hand on both: pitch Ø33.94 each (m_n·N / cos β), shafts 33.94 mm apart; ratio 1 : 1 (N₂/N₁, not the diameters). The second gear's phase was found by search to the touching position.\n- Brown's No. 43 (gears transmitting rotary motion between shafts arranged obliquely, another form).\n- Parts (each has its own page): crossed-helical-gear-mn1-5-16t-beta45-rh-bore6, linear-shafts-h6.\n- Brown's movement No. 43 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.\n\nparameter  value\nnormal module  1.5\nteeth  16 / 16\nhelix  45° RH both\nshaft angle  90°, offset\ncentre distance  33.94 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. 43: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_043.html\n\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/crossed-helical-gears-mechanism/index.json\nAPI: https://xemstudio.com/api/geometry?object=crossed-helical-gears-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. 43: figure, his text and an animation",
   "url": "https://507movements.com/mm_043.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": [
  "crossed-helical-gear-mn1-5-16t-beta45-rh-bore6",
  "linear-shafts-h6"
 ],
 "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 do crossed helical gears connect shafts that do not meet?",
   "a": "Two helical gears of the same hand on shafts that cross without meeting: the shaft angle equals the sum of the helix angles (45° + 45° = 90° here). The teeth touch at a point and slide along each other, so they suit light loads — instrument drives, distributor and oil-pump drives."
  }
 ],
 "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": "crossed-helical-gears-mechanism-assembly",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/crossed-helical-gears-mechanism/crossed-helical-gears-mechanism-assembly.step",
   "stl": "https://xemstudio.com/files/hardware/crossed-helical-gears-mechanism/crossed-helical-gears-mechanism-assembly.stl",
   "note": "Assembled mechanism, all parts placed at one pose (STEP keeps each part separate)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/crossed-helical-gears-mechanism/index.md"
}