{
 "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": "geneva-stop-winding-stop-mechanism",
 "name": "Geneva stop (Maltese cross stop-work): finger wheel limited to four turns",
 "kind": "hardware",
 "category": "Mechanisms",
 "group": "Intermittent motion",
 "year": null,
 "question": "How does a Geneva stop limit the number of turns?",
 "tags": [
  "mechanism",
  "intermittent motion",
  "kinematics",
  "507 mechanical movements"
 ],
 "aliases": [
  "geneva stop",
  "maltese cross stop",
  "stop work",
  "winding stop",
  "geneva mechanism",
  "parada de Ginebra (cruz de Malta)",
  "Malteserkreuz-Gesperre (Aufzugsbegrenzung)"
 ],
 "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/geneva-stop-winding-stop-mechanism/",
 "sheet_txt": "https://xemstudio.com/objects/geneva-stop-winding-stop-mechanism/sheet.txt",
 "sheet": {
  "basis": "Xem Studio design following Brown No. 212 (1868)",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Resize: multiply every length by one factor k and the motion stays identical: angles, ratios, timing and the formulas below do not change, because a mechanism's motion depends only on the ratios of its lengths. Here, scales with k: centres; stays the same: star, turns allowed, engagement; step to the nearest standard size (and redraw the hole or pocket it fits): pin.",
   "Resize: fit clearances stay in mm (a slide fit is the same gap at any size); keep every printed wall and pin at least two nozzle widths; mass grows with k³ but part strength only with k², so at k = 2 parts are about 8× heavier and 4× stronger: check pins and thin links when scaling up.",
   "A finger wheel with one pin indexes a five-position Maltese cross one position per turn, the locking disc holding the cross still in between (a Geneva drive). One of the five positions is not a slot but a convex tooth: when the pin comes round to it the tooth will not let it in, and the finger wheel is stopped — after four turns in one direction (and four back). Brown: used in Swiss watches to limit the winding; the convex curved portion of the star is the stop.",
   "Standard Geneva proportions on 40 mm centres: pin radius a·sin 36° = 23.51, star tip radius a·cos 36° = 32.36, so the pin enters and leaves each slot along the slot (no shock); Ø4 pin in 4 mm slots, locking disc Ø41.02 cut back by the star's exact sweep. Checked at ten wheel angles through an indexing and at the last slot before the stop: no overlap beyond contact; with the stop tooth in place of a slot the pin collides 6° past the entry angle (75.4 mm³), which is the stop.",
   "Drawn with the pin entering the second slot (-20° before the line of centres), the stop tooth three positions on.",
   "Parts (each has its own page): geneva-stop-finger-wheel-r23-5-pin4, geneva-stop-star-5-positions-4-slots-r32-4, linear-shafts-h6.",
   "Brown's movement No. 212 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size."
  ],
  "table": {
   "columns": [
    "parameter",
    "value"
   ],
   "rows": [
    [
     "centres",
     "40 mm"
    ],
    [
     "star",
     "5 positions: 4 slots + 1 stop tooth"
    ],
    [
     "pin",
     "Ø4 at r 23.51"
    ],
    [
     "turns allowed",
     "4"
    ],
    [
     "engagement",
     "108° of the wheel's turn per index"
    ]
   ]
  }
 },
 "sheet_text": "Geneva stop (Maltese cross stop-work): finger wheel limited to four turns — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/geneva-stop-winding-stop-mechanism/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)\nBasis: Xem Studio design following Brown No. 212 (1868)\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Resize: multiply every length by one factor k and the motion stays identical: angles, ratios, timing and the formulas below do not change, because a mechanism's motion depends only on the ratios of its lengths. Here, scales with k: centres; stays the same: star, turns allowed, engagement; step to the nearest standard size (and redraw the hole or pocket it fits): pin.\n- Resize: fit clearances stay in mm (a slide fit is the same gap at any size); keep every printed wall and pin at least two nozzle widths; mass grows with k³ but part strength only with k², so at k = 2 parts are about 8× heavier and 4× stronger: check pins and thin links when scaling up.\n- A finger wheel with one pin indexes a five-position Maltese cross one position per turn, the locking disc holding the cross still in between (a Geneva drive). One of the five positions is not a slot but a convex tooth: when the pin comes round to it the tooth will not let it in, and the finger wheel is stopped — after four turns in one direction (and four back). Brown: used in Swiss watches to limit the winding; the convex curved portion of the star is the stop.\n- Standard Geneva proportions on 40 mm centres: pin radius a·sin 36° = 23.51, star tip radius a·cos 36° = 32.36, so the pin enters and leaves each slot along the slot (no shock); Ø4 pin in 4 mm slots, locking disc Ø41.02 cut back by the star's exact sweep. Checked at ten wheel angles through an indexing and at the last slot before the stop: no overlap beyond contact; with the stop tooth in place of a slot the pin collides 6° past the entry angle (75.4 mm³), which is the stop.\n- Drawn with the pin entering the second slot (-20° before the line of centres), the stop tooth three positions on.\n- Parts (each has its own page): geneva-stop-finger-wheel-r23-5-pin4, geneva-stop-star-5-positions-4-slots-r32-4, linear-shafts-h6.\n- Brown's movement No. 212 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.\n\nparameter  value\ncentres  40 mm\nstar  5 positions: 4 slots + 1 stop tooth\npin  Ø4 at r 23.51\nturns allowed  4\nengagement  108° of the wheel's turn per index\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. 212: figure, his text and an animation — web — Publisher's page; dimensions are facts — https://507movements.com/mm_212.html\n\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/geneva-stop-winding-stop-mechanism/index.json\nAPI: https://xemstudio.com/api/geometry?object=geneva-stop-winding-stop-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. 212: figure, his text and an animation",
   "url": "https://507movements.com/mm_212.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": [
  "geneva-stop-finger-wheel-r23-5-pin4",
  "geneva-stop-star-5-positions-4-slots-r32-4",
  "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 does a Geneva stop limit the number of turns?",
   "a": "A finger wheel with one pin indexes a five-position Maltese cross one position per turn, the locking disc holding the cross still in between (a Geneva drive). One of the five positions is not a slot but a convex tooth: when the pin comes round to it the tooth will not let it in, and the finger wheel is stopped — after four turns in one direction (and four back). Brown: used in Swiss watches to limit the winding; the convex curved portion of the star is the stop."
  },
  {
   "q": "What is the difference between a Geneva drive and a Geneva stop?",
   "a": "The same wheel and cross; the stop has one slot replaced by a convex tooth, so the cross cannot go round and the driver is limited to n − 1 turns."
  }
 ],
 "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": "geneva-stop-winding-stop-mechanism-assembly",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/geneva-stop-winding-stop-mechanism/geneva-stop-winding-stop-mechanism-assembly.step",
   "stl": "https://xemstudio.com/files/hardware/geneva-stop-winding-stop-mechanism/geneva-stop-winding-stop-mechanism-assembly.stl",
   "note": "Assembled mechanism, all parts placed at one pose (STEP keeps each part separate)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/geneva-stop-winding-stop-mechanism/index.md"
}