{
 "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": "brushless-outrunner-2204",
 "name": "2204 brushless outrunner: Ø27.9 × 29.2 mm, 16 × 19 M3 mount",
 "kind": "hardware",
 "category": "Electronics",
 "group": "Motors",
 "year": null,
 "question": "What are the dimensions of a 2204 brushless motor?",
 "tags": [
  "2204",
  "brushless",
  "outrunner",
  "bldc",
  "drone motor",
  "motor",
  "motor envelope",
  "stirling"
 ],
 "aliases": [
  "2204 motor dimensions",
  "2204 brushless motor size",
  "2204 motor mount pattern",
  "2204 motor step",
  "2204 motor stl",
  "2204 outrunner mounting holes"
 ],
 "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/brushless-outrunner-2204/",
 "sheet_txt": "https://xemstudio.com/objects/brushless-outrunner-2204/sheet.txt",
 "sheet": {
  "basis": "RCDrone listing of the EMAX MT2204 II drawing values. Envelope only: the outside of the motor at its published sizes. The windings, magnets, brushes and bearings inside are not drawn.",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Envelope only: the outside of the motor at its published sizes. The windings, magnets, brushes and bearings inside are not drawn.",
   "2204 names the stator: 22 mm diameter, 4 mm tall. The outside below is one maker's 2204; bell size, shaft and mount differ between makers.",
   "The bell is Ø27.9 and the motor is 29.2 mm tall overall, of which 12.5 is the Ø5 shaft above the bell; the top 7.5 of it is the M5 prop thread (drawn plain at Ø5). The base below the bell is drawn at the bell Ø as an envelope.",
   "Base mount: four M3 holes in a cross, two 16 mm apart and two 19 mm apart. The listing gives no thread depth, so they are drawn Ø3.0 × 3.0 deep only to mark them.",
   "The leads and the Ø8 centre boss on the drawing are not drawn (its height is not given).",
   "In DIY Stirling builds, brushless outrunners are driven by the engine as three-phase generators; the AC from the three leads is rectified for a load."
  ],
  "table": {
   "columns": [
    "feature",
    "mm",
    "from"
   ],
   "rows": [
    [
     "bell",
     "Ø27.9",
     "RCDrone / EMAX MT2204 II"
    ],
    [
     "overall height",
     "29.2",
     "RCDrone / EMAX MT2204 II"
    ],
    [
     "bell and base height",
     "16.7 (29.2 − 12.5)",
     "RCDrone / EMAX MT2204 II"
    ],
    [
     "shaft above the bell",
     "Ø5 × 12.5, M5 thread 7.5",
     "RCDrone / EMAX MT2204 II"
    ],
    [
     "base holes",
     "4 × M3, cross 16 × 19",
     "RCDrone / EMAX MT2204 II"
    ],
    [
     "stator",
     "22 × 4 (the name)",
     "size name"
    ]
   ]
  }
 },
 "sheet_text": "2204 brushless outrunner: Ø27.9 × 29.2 mm, 16 × 19 M3 mount — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/brushless-outrunner-2204/  (CC BY 4.0)\nBasis: RCDrone listing of the EMAX MT2204 II drawing values. Envelope only: the outside of the motor at its published sizes. The windings, magnets, brushes and bearings inside are not drawn.\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Envelope only: the outside of the motor at its published sizes. The windings, magnets, brushes and bearings inside are not drawn.\n- 2204 names the stator: 22 mm diameter, 4 mm tall. The outside below is one maker's 2204; bell size, shaft and mount differ between makers.\n- The bell is Ø27.9 and the motor is 29.2 mm tall overall, of which 12.5 is the Ø5 shaft above the bell; the top 7.5 of it is the M5 prop thread (drawn plain at Ø5). The base below the bell is drawn at the bell Ø as an envelope.\n- Base mount: four M3 holes in a cross, two 16 mm apart and two 19 mm apart. The listing gives no thread depth, so they are drawn Ø3.0 × 3.0 deep only to mark them.\n- The leads and the Ø8 centre boss on the drawing are not drawn (its height is not given).\n- In DIY Stirling builds, brushless outrunners are driven by the engine as three-phase generators; the AC from the three leads is rectified for a load.\n\nfeature  mm  from\nbell  Ø27.9  RCDrone / EMAX MT2204 II\noverall height  29.2  RCDrone / EMAX MT2204 II\nbell and base height  16.7 (29.2 − 12.5)  RCDrone / EMAX MT2204 II\nshaft above the bell  Ø5 × 12.5, M5 thread 7.5  RCDrone / EMAX MT2204 II\nbase holes  4 × M3, cross 16 × 19  RCDrone / EMAX MT2204 II\nstator  22 × 4 (the name)  size name\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- RCDrone (EMAX MT2204 II drawing values): 2204 outrunner: Ø27.9, 29.2 overall, M5 shaft 12.5 out (7.5 threaded), 4 × M3 on 16 and 19 — web — listing [verify license at link] — https://rcdrone.top/products/mt2204%E2%85%B1-2600kv-brushless-motor-with-cw-ccw-options\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/brushless-outrunner-2204/index.json\nAPI: https://xemstudio.com/api/geometry?object=brushless-outrunner-2204\n",
 "sources": [
  {
   "publisher": "RCDrone (EMAX MT2204 II drawing values)",
   "title": "2204 outrunner: Ø27.9, 29.2 overall, M5 shaft 12.5 out (7.5 threaded), 4 × M3 on 16 and 19",
   "url": "https://rcdrone.top/products/mt2204%E2%85%B1-2600kv-brushless-motor-with-cw-ccw-options",
   "formats": [
    "web"
   ],
   "license": "listing",
   "license_verified": false,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "gt2-pulleys",
  "shaft-couplers",
  "shaft-collars",
  "encoder-disc",
  "axial-flux-rotor",
  "socket-head-cap-screws-metric"
 ],
 "fits": [
  {
   "role": "Connects to",
   "items": [
    {
     "slug": "socket-head-cap-screws-metric",
     "why": "four M3 into the base, 16 × 19 cross"
    },
    {
     "slug": "gt2-pulleys",
     "why": "Ø5 bore on the Ø5 shaft (slide)"
    },
    {
     "slug": "shaft-couplers",
     "why": "5 mm bore on the Ø5 shaft (slide)"
    }
   ]
  },
  {
   "role": "Alternatives",
   "items": [
    {
     "slug": "axial-flux-rotor",
     "why": "a home-made axial-flux generator instead"
    },
    {
     "slug": "nema-17-stepper",
     "why": "a stepper run as a two-phase generator"
    }
   ]
  }
 ],
 "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": [
  {
   "feature": "shaft",
   "exact": "Ø5 (M5 thread on the top 7.5)",
   "mates": "pulley, coupler or prop-adapter bore",
   "fit": "slide",
   "files": "outrunner-2204"
  },
  {
   "feature": "base holes",
   "exact": "4 × M3, cross 16 × 19 (drawn 3.0 deep as position marks)",
   "mates": "M3 screws through the mount",
   "fit": "designed",
   "files": "outrunner-2204"
  },
  {
   "feature": "bell",
   "exact": "Ø27.9, turns with the shaft",
   "mates": "clearance in the mount (no contact)",
   "fit": "designed",
   "files": "outrunner-2204"
  }
 ],
 "fit_classes": {
  "press": "stays put: pin, tube, bearing or magnet held by interference. Typical FDM: hole +0.0 to +0.1 mm on diameter.",
  "slide": "assembles by hand and is held by a grub, pinch or clamp: shaft in a hub, rod in a socket, spigot in a bore. Typical FDM: +0.2 mm.",
  "run": "turns or slides in use: pin in a link, rod through a guide. Typical FDM: +0.3 mm.",
  "socket": "large sliding fit: syringe barrel, sleeve, bobbin in a bore. Typical FDM: +0.3 mm.",
  "clamp": "split part that closes on the mating part with screws: make it at size.",
  "designed": "a gap that is part of the design (piston fit option, displacer gap, air gap): do not change."
 },
 "faq": [
  {
   "q": "What are 2204 motor dimensions?",
   "a": "One common 2204 (EMAX MT2204 II) is Ø27.9 × 29.2 mm overall with a Ø5 / M5 shaft 12.5 mm out of the top and four M3 base holes on a 16 × 19 cross."
  },
  {
   "q": "What is the 2204 motor mount pattern?",
   "a": "16 × 19 mm with M3 screws on this motor (two holes 16 apart, two 19 apart). Other makers use 16 × 16 or 12 × 12: check the motor in hand."
  },
  {
   "q": "Can a brushless outrunner be used as a generator?",
   "a": "Yes: turned by an engine it puts out three-phase AC on its three leads; a three-phase bridge rectifier turns it into DC."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "outrunner-2204",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/brushless-outrunner-2204/outrunner-2204.step",
   "stl": "https://xemstudio.com/files/hardware/brushless-outrunner-2204/outrunner-2204.stl",
   "note": "2204 outrunner envelope: Ø27.9 × 16.7 bell and base, Ø5 (M5) shaft 12.5 out of the top, 4 × M3 on 16 × 19 cross (3.0 deep position marks)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/brushless-outrunner-2204/index.md"
}