{
 "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": "crown-wheel-m1-5-54t-for-18t-pinion",
 "name": "Crown wheel (face gear), module 1.5, 54 teeth, generated by an 18-tooth spur pinion",
 "kind": "modern",
 "category": "Mechanisms",
 "group": "Gears",
 "year": null,
 "question": "How are the teeth of a crown wheel shaped?",
 "tags": [
  "mechanism part",
  "507 mechanical movements"
 ],
 "aliases": [
  "crown wheel",
  "face gear",
  "contrate wheel",
  "crown gear",
  "rueda de corona (engranaje frontal)",
  "Kronenrad"
 ],
 "overall_mm": {
  "length": 89,
  "width": 89.15,
  "height": 9.63
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": false,
 "free_files": 1,
 "url": "https://xemstudio.com/objects/crown-wheel-m1-5-54t-for-18t-pinion/",
 "sheet_txt": "https://xemstudio.com/objects/crown-wheel-m1-5-54t-for-18t-pinion/sheet.txt",
 "sheet": {
  "basis": "Xem Studio design following Brown's figure (1868); true size, no printing allowance",
  "overall_mm": {
   "length": 89,
   "width": 89.15,
   "height": 9.63
  },
  "notes": [
   "Face gear: 54 teeth standing on the face of a Ø89 disc (Ø8 bore), from radius 37.5 to 44.5 mm, each tooth the envelope of the module 1.5, 18-tooth involute spur pinion it runs with (the catalog gear, its own root form included): the pinion's axis lies in the wheel's pitch plane, 13.5 mm (its pitch radius) above the tooth-root plane's offset, and the pair turns at 3 : 1 while the pinion's teeth sweep the spaces — computed in 7 planes across the face at 0.25° steps and lofted through them (spline fit within 0.008 mm).",
   "Tooth top at +1.5 mm above the pitch plane, space bottom at −1.875 mm (0.25 m clearance under the pinion's tip); the toothed band is a 54-gon, so every tooth ends flat at its own inner and outer radius. The tooth form changes across the face: wider and undercut toward the centre, pointed toward the rim — which is why a face gear's face width is short (here 7 mm, from 3 modules inside the nominal pitch radius 40.5 to 4 outside).",
   "Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features)."
  ],
  "table": {
   "columns": [
    "dimension",
    "value"
   ],
   "rows": [
    [
     "module",
     "1.5"
    ],
    [
     "teeth",
     "54"
    ],
    [
     "pinion",
     "18 T spur (catalog gear-m1-5-18t), axis in the pitch plane"
    ],
    [
     "face",
     "r 37.5 → 44.5 mm (7 mm)"
    ],
    [
     "tooth top / root",
     "+1.5 / −1.875 mm from the pitch plane"
    ],
    [
     "disc",
     "Ø89 × 6 under the teeth, Ø8 bore"
    ],
    [
     "ratio",
     "3 : 1"
    ]
   ]
  }
 },
 "sheet_text": "Crown wheel (face gear), module 1.5, 54 teeth, generated by an 18-tooth spur pinion — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/crown-wheel-m1-5-54t-for-18t-pinion/  (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 89.0, width 89.15, height 9.63\n- Face gear: 54 teeth standing on the face of a Ø89 disc (Ø8 bore), from radius 37.5 to 44.5 mm, each tooth the envelope of the module 1.5, 18-tooth involute spur pinion it runs with (the catalog gear, its own root form included): the pinion's axis lies in the wheel's pitch plane, 13.5 mm (its pitch radius) above the tooth-root plane's offset, and the pair turns at 3 : 1 while the pinion's teeth sweep the spaces — computed in 7 planes across the face at 0.25° steps and lofted through them (spline fit within 0.008 mm).\n- Tooth top at +1.5 mm above the pitch plane, space bottom at −1.875 mm (0.25 m clearance under the pinion's tip); the toothed band is a 54-gon, so every tooth ends flat at its own inner and outer radius. The tooth form changes across the face: wider and undercut toward the centre, pointed toward the rim — which is why a face gear's face width is short (here 7 mm, from 3 modules inside the nominal pitch radius 40.5 to 4 outside).\n- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).\n\ndimension  value\nmodule  1.5\nteeth  54\npinion  18 T spur (catalog gear-m1-5-18t), axis in the pitch plane\nface  r 37.5 → 44.5 mm (7 mm)\ntooth top / root  +1.5 / −1.875 mm from the pitch plane\ndisc  Ø89 × 6 under the teeth, Ø8 bore\nratio  3 : 1\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. 26: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_026.html\n- Xem Studio: drawing — web — Publisher's page; dimensions are facts — https://xemstudio.com/objects/crown-wheel-spur-pinion-mechanism/\n\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/crown-wheel-m1-5-54t-for-18t-pinion/index.json\nAPI: https://xemstudio.com/api/geometry?object=crown-wheel-m1-5-54t-for-18t-pinion\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. 26: figure, his text and an animation",
   "url": "https://507movements.com/mm_026.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/crown-wheel-spur-pinion-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": [
  "crown-wheel-spur-pinion-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": "How are the teeth of a crown wheel shaped?",
   "a": "Face gear: 54 teeth standing on the face of a Ø89 disc (Ø8 bore), from radius 37.5 to 44.5 mm, each tooth the envelope of the module 1.5, 18-tooth involute spur pinion it runs with (the catalog gear, its own root form included): the pinion's axis lies in the wheel's pitch plane, 13.5 mm (its pitch radius) above the tooth-root plane's offset, and the pair turns at 3 : 1 while the pinion's teeth sweep the spaces — computed in 7 planes across the face at 0.25° steps and lofted through them (spline fit within 0.008 mm)."
  }
 ],
 "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": "crown-wheel-m1-5-54t-for-18t-pinion",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/crown-wheel-m1-5-54t-for-18t-pinion/crown-wheel-m1-5-54t-for-18t-pinion.step",
   "stl": "https://xemstudio.com/files/hardware/crown-wheel-m1-5-54t-for-18t-pinion/crown-wheel-m1-5-54t-for-18t-pinion.stl",
   "note": "crown wheel, axis Z, pitch plane z = 0, a space centred on +X"
  }
 ],
 "markdown": "https://xemstudio.com/objects/crown-wheel-m1-5-54t-for-18t-pinion/index.md"
}