{
 "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": "print-in-place-planetary-gearbox",
 "name": "Print-in-place: planetary gearbox, herringbone, 4 : 1",
 "kind": "hardware",
 "category": "3D printing",
 "group": "Print-in-place mechanisms",
 "year": null,
 "question": "How do you 3D print a planetary gearbox already assembled?",
 "tags": [
  "3d printable",
  "print in place",
  "no assembly",
  "no supports",
  "mechanism",
  "stl",
  "step",
  "gears",
  "planetary",
  "herringbone",
  "gearbox"
 ],
 "aliases": [
  "print in place planetary gearbox",
  "print in place gears",
  "herringbone planetary gear stl",
  "3d printed planetary gearbox",
  "gear bearing print in place"
 ],
 "overall_mm": {
  "length": 112,
  "width": 112,
  "height": 48
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": false,
 "free_files": 7,
 "url": "https://xemstudio.com/objects/print-in-place-planetary-gearbox/",
 "sheet_txt": "https://xemstudio.com/objects/print-in-place-planetary-gearbox/sheet.txt",
 "sheet": {
  "basis": "Xem Studio design; involute gearing per ISO 53 (20° basic rack), double helical 30°, normal module 1.5; one designed running gap of 0.40 mm",
  "overall_mm": {
   "length": 112,
   "width": 112,
   "height": 48
  },
  "notes": [
   "3D print in place — prints already assembled, moving, in one job. Drawn at true size with no printer tolerance added; the 0.40 mm running gaps are part of the design.",
   "Running gap 0.40 mm per side, 0.80 mm on diameter — part of the design, drawn as is. On the 45° faces the same 0.40 mm is measured square to the face (0.57 mm along the axis).",
   "Bed: sun, three planets, ring and carrier all stand on the bed: the gears on their bottom faces, the carrier on its three pins (each a 45° cone in a planet's counterbore). The carrier grows up from the pins as three 45° cones that merge into one three-lobed dome above the gears.",
   "Support while printing: herringbone flanks lean 28° (base helix) and the carrier's underside is all 45° cone, 0.40 mm clear of the planet tops and bores; the sun's knob flares out at 45° above the carrier. Nothing is flat over air.",
   "Captured: the herringbone (two opposed 30° helices) locks each planet axially between sun and ring; each planet's 45° counterbore holds the carrier's pin base below it; the carrier's cones close over the planets above. Nothing can come out.",
   "Freeing it: hold the ring and turn the sun knob slowly in both directions until it runs smoothly (a screwdriver fits the slot); the carrier follows at a quarter of the speed.",
   "Motion: continuous; ratio 4 : 1 (sun : carrier, ring fixed); planets spin 1× the sun-relative-to-carrier speed. Checked in the transverse section through a quarter turn of the sun: min gap 0.454 mm in the section (≥ 0.40 square to the flanks).",
   "Involute teeth: 20° normal pressure angle, addendum 1.0 m, dedendum 1.25 m (ring: tips at 0.88 m inside the pitch circle, the catalog ring's rule); every tooth thinned so the running gap is 0.40 mm square to the flanks at the exact centre distance."
  ],
  "table": {
   "columns": [
    "key",
    "value",
    "what"
   ],
   "rows": [
    [
     "gap_mm",
     0.4,
     "running gap per side on every moving interface (radial, axial, under captured parts) — part of the design, not a tolerance"
    ],
    [
     "module_n_mm",
     1.5,
     "normal module"
    ],
    [
     "helix_deg",
     30,
     "herringbone (double helical), 20° normal pressure angle, ISO 53 basic rack"
    ],
    [
     "teeth_sun",
     18,
     ""
    ],
    [
     "teeth_planet",
     18,
     "three planets"
    ],
    [
     "teeth_ring",
     54,
     ""
    ],
    [
     "face_w_mm",
     12,
     "all gears"
    ],
    [
     "ratio",
     "4 : 1",
     "sun in, carrier out, ring fixed"
    ],
    [
     "center_distance_mm",
     31.18,
     "sun to planet"
    ],
    [
     "flank_gap_mm",
     0.4,
     "square to the tooth flanks: sun and planet teeth thinned 0.20 mm per flank (0.226 in the transverse section), ring spaces opened 0.238 (measured in the model: 0.401 sun–planet, 0.402 ring–planet)"
    ],
    [
     "pin_d_mm",
     11,
     "carrier pins, 45° base cone Ø14 on the bed"
    ],
    [
     "bore_d_mm",
     11.8,
     "planet bores, 45° counterbore below"
    ],
    [
     "ring_od_mm",
     112,
     "4 × Ø4.5 on Ø105"
    ],
    [
     "height_mm",
     48,
     "to the top of the sun knob"
    ],
    [
     "planet_axial_play_mm",
     0.86,
     "herringbone end play (computed)"
    ],
    [
     "carrier_holes",
     "3 × Ø3.4 on Ø40",
     "output"
    ],
    [
     "sun_shaft_d_mm",
     7.6,
     "runs in the carrier's Ø8.4 centre bore"
    ]
   ]
  }
 },
 "sheet_text": "Print-in-place: planetary gearbox, herringbone, 4 : 1 — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/print-in-place-planetary-gearbox/  (sheet CC BY 4.0; files Xem Studio Design License, https://xemstudio.com/license/)\nBasis: Xem Studio design; involute gearing per ISO 53 (20° basic rack), double helical 30°, normal module 1.5; one designed running gap of 0.40 mm\nCatalog version: 2026-10-20\n\nOverall (mm): length 112.0, width 112.0, height 48.0\n- 3D print in place — prints already assembled, moving, in one job. Drawn at true size with no printer tolerance added; the 0.40 mm running gaps are part of the design.\n- Running gap 0.40 mm per side, 0.80 mm on diameter — part of the design, drawn as is. On the 45° faces the same 0.40 mm is measured square to the face (0.57 mm along the axis).\n- Bed: sun, three planets, ring and carrier all stand on the bed: the gears on their bottom faces, the carrier on its three pins (each a 45° cone in a planet's counterbore). The carrier grows up from the pins as three 45° cones that merge into one three-lobed dome above the gears.\n- Support while printing: herringbone flanks lean 28° (base helix) and the carrier's underside is all 45° cone, 0.40 mm clear of the planet tops and bores; the sun's knob flares out at 45° above the carrier. Nothing is flat over air.\n- Captured: the herringbone (two opposed 30° helices) locks each planet axially between sun and ring; each planet's 45° counterbore holds the carrier's pin base below it; the carrier's cones close over the planets above. Nothing can come out.\n- Freeing it: hold the ring and turn the sun knob slowly in both directions until it runs smoothly (a screwdriver fits the slot); the carrier follows at a quarter of the speed.\n- Motion: continuous; ratio 4 : 1 (sun : carrier, ring fixed); planets spin 1× the sun-relative-to-carrier speed. Checked in the transverse section through a quarter turn of the sun: min gap 0.454 mm in the section (≥ 0.40 square to the flanks).\n- Involute teeth: 20° normal pressure angle, addendum 1.0 m, dedendum 1.25 m (ring: tips at 0.88 m inside the pitch circle, the catalog ring's rule); every tooth thinned so the running gap is 0.40 mm square to the flanks at the exact centre distance.\n\nkey  value  what\ngap_mm  0.4  running gap per side on every moving interface (radial, axial, under captured parts) — part of the design, not a tolerance\nmodule_n_mm  1.5  normal module\nhelix_deg  30.0  herringbone (double helical), 20° normal pressure angle, ISO 53 basic rack\nteeth_sun  18  \nteeth_planet  18  three planets\nteeth_ring  54  \nface_w_mm  12.0  all gears\nratio  4 : 1  sun in, carrier out, ring fixed\ncenter_distance_mm  31.18  sun to planet\nflank_gap_mm  0.4  square to the tooth flanks: sun and planet teeth thinned 0.20 mm per flank (0.226 in the transverse section), ring spaces opened 0.238 (measured in the model: 0.401 sun–planet, 0.402 ring–planet)\npin_d_mm  11.0  carrier pins, 45° base cone Ø14 on the bed\nbore_d_mm  11.8  planet bores, 45° counterbore below\nring_od_mm  112  4 × Ø4.5 on Ø105\nheight_mm  48.0  to the top of the sun knob\nplanet_axial_play_mm  0.86  herringbone end play (computed)\ncarrier_holes  3 × Ø3.4 on Ø40  output\nsun_shaft_d_mm  7.6  runs in the carrier's Ø8.4 centre bore\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Xem Studio: Print-in-place mechanism design (geometry computed in the generator) — web — Xem Studio design — https://xemstudio.com/\n\nFree files (Xem Studio Design License, Xem Studio; STEP + STL, 7 parts): https://xemstudio.com/files/hardware/print-in-place-planetary-gearbox/index.json\nAPI: https://xemstudio.com/api/geometry?object=print-in-place-planetary-gearbox\n",
 "sources": [
  {
   "publisher": "Xem Studio",
   "title": "Print-in-place mechanism design (geometry computed in the generator)",
   "url": "https://xemstudio.com/",
   "formats": [
    "web"
   ],
   "license": "Xem Studio design",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "print-in-place-captive-wheel-axle",
  "print-in-place-barrel-hinge-180",
  "print-in-place-multi-knuckle-hinge",
  "print-in-place-captive-turntable",
  "print-in-place-dovetail-slider",
  "print-in-place-articulated-chain",
  "print-in-place-ball-joint",
  "print-in-place-push-button-flexure"
 ],
 "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 gears kept from falling out?",
   "a": "Herringbone teeth: the two opposed helices of each planet interlock with the sun and the ring, so no gear can slide axially; the carrier hangs on the planets by its 45° pin bases."
  },
  {
   "q": "What is the gear ratio?",
   "a": "4 : 1 — sun 18 teeth, ring 54: carrier turns once for every 4 turns of the sun."
  }
 ],
 "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": "print-in-place-planetary-gearbox-assembly",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/print-in-place-planetary-gearbox/print-in-place-planetary-gearbox-assembly.step",
   "stl": "https://xemstudio.com/files/hardware/print-in-place-planetary-gearbox/print-in-place-planetary-gearbox-assembly.stl",
   "note": "The whole print as laid on the bed (6 bodies, already assembled); STEP keeps each moving body a separate solid"
  },
  {
   "file": "print-in-place-planetary-gearbox-ring",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/print-in-place-planetary-gearbox/print-in-place-planetary-gearbox-ring.step",
   "stl": "https://xemstudio.com/files/hardware/print-in-place-planetary-gearbox/print-in-place-planetary-gearbox-ring.stl",
   "note": "Ring gear 54 teeth, herringbone, Ø112 × 12, 4 × Ø4.5"
  },
  {
   "file": "print-in-place-planetary-gearbox-sun",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/print-in-place-planetary-gearbox/print-in-place-planetary-gearbox-sun.step",
   "stl": "https://xemstudio.com/files/hardware/print-in-place-planetary-gearbox/print-in-place-planetary-gearbox-sun.stl",
   "note": "Sun 18 teeth with shaft Ø7.6 and slotted knob"
  },
  {
   "file": "print-in-place-planetary-gearbox-planet-1",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/print-in-place-planetary-gearbox/print-in-place-planetary-gearbox-planet-1.step",
   "stl": "https://xemstudio.com/files/hardware/print-in-place-planetary-gearbox/print-in-place-planetary-gearbox-planet-1.stl",
   "note": "Planet 18 teeth, Ø11.8 bore with 45° counterbore"
  },
  {
   "file": "print-in-place-planetary-gearbox-planet-2",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/print-in-place-planetary-gearbox/print-in-place-planetary-gearbox-planet-2.step",
   "stl": "https://xemstudio.com/files/hardware/print-in-place-planetary-gearbox/print-in-place-planetary-gearbox-planet-2.stl",
   "note": "Planet 18 teeth, Ø11.8 bore with 45° counterbore"
  },
  {
   "file": "print-in-place-planetary-gearbox-planet-3",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/print-in-place-planetary-gearbox/print-in-place-planetary-gearbox-planet-3.step",
   "stl": "https://xemstudio.com/files/hardware/print-in-place-planetary-gearbox/print-in-place-planetary-gearbox-planet-3.stl",
   "note": "Planet 18 teeth, Ø11.8 bore with 45° counterbore"
  },
  {
   "file": "print-in-place-planetary-gearbox-carrier",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "Xem Studio Design License",
   "step": "https://xemstudio.com/files/hardware/print-in-place-planetary-gearbox/print-in-place-planetary-gearbox-carrier.step",
   "stl": "https://xemstudio.com/files/hardware/print-in-place-planetary-gearbox/print-in-place-planetary-gearbox-carrier.stl",
   "note": "Carrier: three Ø11 pins on 45° bases, 45° cone dome, Ø8.4 centre bore, 3 × Ø3.4"
  }
 ],
 "markdown": "https://xemstudio.com/objects/print-in-place-planetary-gearbox/index.md"
}