{
 "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": "axial-flux-rotor",
 "name": "Axial-flux rotor plates: Ø90 with 12 magnets (Ø8 bore), Ø70 with 8 magnets (Ø5 bore)",
 "kind": "hardware",
 "category": "Stirling engines",
 "group": "Generators & instruments",
 "year": null,
 "question": "How do I build a small axial flux generator rotor with neodymium magnets?",
 "tags": [
  "axial flux",
  "rotor",
  "generator",
  "alternator",
  "magnet",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "axial flux rotor",
  "axial flux generator 3d print",
  "diy alternator neodymium magnets",
  "12 pole rotor stl",
  "magnet rotor plate"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 2,
 "url": "https://xemstudio.com/objects/axial-flux-rotor/",
 "sheet_txt": "https://xemstudio.com/objects/axial-flux-rotor/sheet.txt",
 "sheet": {
  "basis": "Coreless axial-flux layout: 12 poles on Ø90 or 8 poles on Ø70, pockets for Ø10 × 3 disc magnets, hub sized to the Ø8 / Ø5 shaft",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "The Ø90 rotor is a 5 mm plate with 12 pockets Ø10 × 3 deep on a Ø72 circle, a Ø32 × 8 hub underneath and a Ø8 bore through (13 mm overall).",
   "The Ø70 rotor has 8 pockets Ø10 × 3 on a Ø52 circle, a Ø26 × 8 hub and a Ø5 bore.",
   "A Ø2.5 radial hole (M3 tap drill) enters the hub 4 mm below the plate for a grub screw.",
   "Magnets alternate N-S around the ring; a second rotor facing it (N opposite S across the stator) doubles the flux.",
   "Frequency = rpm × poles / 120: 600 rpm on the 12-pole rotor is 60 Hz."
  ],
  "table": {
   "columns": [
    "rotor",
    "plate_mm",
    "magnets",
    "magnet_circle_mm",
    "hub_mm",
    "bore_mm"
   ],
   "rows": [
    [
     "rotor-90-12x-10x3-b8",
     "Ø90 × 5",
     "12 × Ø10×3",
     72,
     "Ø32 × 8",
     8
    ],
    [
     "rotor-70-8x-10x3-b5",
     "Ø70 × 5",
     "8 × Ø10×3",
     52,
     "Ø26 × 8",
     5
    ]
   ]
  }
 },
 "sheet_text": "Axial-flux rotor plates: Ø90 with 12 magnets (Ø8 bore), Ø70 with 8 magnets (Ø5 bore) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/axial-flux-rotor/  (CC BY 4.0)\nBasis: Coreless axial-flux layout: 12 poles on Ø90 or 8 poles on Ø70, pockets for Ø10 × 3 disc magnets, hub sized to the Ø8 / Ø5 shaft\nCatalog version: 2026-10-20\n\nSizes: see table below\n- The Ø90 rotor is a 5 mm plate with 12 pockets Ø10 × 3 deep on a Ø72 circle, a Ø32 × 8 hub underneath and a Ø8 bore through (13 mm overall).\n- The Ø70 rotor has 8 pockets Ø10 × 3 on a Ø52 circle, a Ø26 × 8 hub and a Ø5 bore.\n- A Ø2.5 radial hole (M3 tap drill) enters the hub 4 mm below the plate for a grub screw.\n- Magnets alternate N-S around the ring; a second rotor facing it (N opposite S across the stator) doubles the flux.\n- Frequency = rpm × poles / 120: 600 rpm on the 12-pole rotor is 60 Hz.\n\nrotor  plate_mm  magnets  magnet_circle_mm  hub_mm  bore_mm\nrotor-90-12x-10x3-b8  Ø90 × 5  12 × Ø10×3  72  Ø32 × 8  8\nrotor-70-8x-10x3-b5  Ø70 × 5  8 × Ø10×3  52  Ø26 × 8  5\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Wikipedia: Axial flux motor — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Axial_flux_motor\n- Wikipedia: Alternator — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Alternator\n- Hugh Piggott: A Wind Turbine Recipe Book (axial-flux alternator design) — web, PDF — Author's site [verify license at link] — http://scoraigwind.co.uk/\n- Long Earth Society: Engine and rig builds — web, video — LES site — https://longearthsociety.com/engineering/\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 2 parts): https://xemstudio.com/files/hardware/axial-flux-rotor/index.json\nAPI: https://xemstudio.com/api/geometry?object=axial-flux-rotor\n",
 "sources": [
  {
   "publisher": "Wikipedia",
   "title": "Axial flux motor",
   "url": "https://en.wikipedia.org/wiki/Axial_flux_motor",
   "formats": [
    "web"
   ],
   "license": "CC BY-SA 4.0 (text)",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Wikipedia",
   "title": "Alternator",
   "url": "https://en.wikipedia.org/wiki/Alternator",
   "formats": [
    "web"
   ],
   "license": "CC BY-SA 4.0 (text)",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Hugh Piggott",
   "title": "A Wind Turbine Recipe Book (axial-flux alternator design)",
   "url": "http://scoraigwind.co.uk/",
   "formats": [
    "web",
    "PDF"
   ],
   "license": "Author's site",
   "license_verified": false,
   "hosted": false
  },
  {
   "publisher": "Long Earth Society",
   "title": "Engine and rig builds",
   "url": "https://longearthsociety.com/engineering/",
   "formats": [
    "web",
    "video"
   ],
   "license": "LES site",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "axial-flux-stator",
  "coil-bobbin",
  "hall-sensor-mount",
  "neodymium-disc-magnets",
  "608-bearing",
  "metric-shafts"
 ],
 "fits": [
  {
   "role": "Parts that fit it",
   "items": [
    {
     "slug": "hall-sensor-mount",
     "why": "faces a rotor magnet: 12 pulses per revolution"
    }
   ]
  },
  {
   "role": "Goes in or on",
   "items": [
    {
     "slug": "metric-shafts",
     "why": "Ø8 / Ø5 bore on the shaft, M3 grub"
    }
   ]
  },
  {
   "role": "Connects to",
   "items": [
    {
     "slug": "neodymium-disc-magnets",
     "why": "Ø10 × 3 magnets in the Ø10 × 3 pockets (press)"
    },
    {
     "slug": "608-bearing",
     "why": "the Ø8 flywheel shaft runs in 608s"
    }
   ]
  },
  {
   "role": "Also needed",
   "items": [
    {
     "slug": "axial-flux-stator",
     "why": "coils on the same Ø72 / Ø52 circle"
    }
   ]
  }
 ],
 "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": "rotor bore",
   "exact": "Ø8 / Ø5",
   "mates": "shaft (M3 grub)",
   "fit": "slide",
   "files": "rotor-"
  },
  {
   "feature": "magnet pockets",
   "exact": "Ø10 × 3",
   "mates": "Ø10 × 3 disc magnet",
   "fit": "press",
   "files": "rotor-"
  },
  {
   "feature": "grub hole",
   "exact": "Ø2.5",
   "mates": "M3 tap drill",
   "fit": "designed",
   "files": "rotor-"
  }
 ],
 "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": "How many magnets for a small axial flux generator?",
   "a": "12 magnets with 9 coils (3-phase) on a Ø90 rotor, or 8 magnets with 6 coils on Ø70; poles alternate N-S."
  },
  {
   "q": "What magnets fit the rotor?",
   "a": "Ø10 × 3 disc magnets; the pockets are drawn Ø10 × 3 exact (press, see Mating features)."
  },
  {
   "q": "What frequency does it make?",
   "a": "Rpm × poles / 120: 60 Hz at 600 rpm on the 12-pole rotor."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "rotor-90-12x-10x3-b8",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/axial-flux-generator-kit/rotor-90-12x-10x3-b8.step",
   "stl": "https://xemstudio.com/files/hardware/axial-flux-generator-kit/rotor-90-12x-10x3-b8.stl",
   "note": "rotor plate Ø90 × 5: 12 pockets for Ø10 × 3 magnets (alternating poles) on a 66 mm circle, Ø8 bore hub with set screw; two face each other across the stator"
  },
  {
   "file": "rotor-70-8x-10x3-b5",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/axial-flux-generator-kit/rotor-70-8x-10x3-b5.step",
   "stl": "https://xemstudio.com/files/hardware/axial-flux-generator-kit/rotor-70-8x-10x3-b5.stl",
   "note": "rotor plate Ø70 × 5: 8 pockets for Ø10 × 3 magnets on a 46 mm circle, Ø5 bore hub with set screw"
  }
 ],
 "markdown": "https://xemstudio.com/objects/axial-flux-rotor/index.md"
}