{
 "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": "gear-racks",
 "name": "Gear racks: module 1 (100 mm) and module 2 (150 mm)",
 "kind": "hardware",
 "category": "Stirling engines",
 "group": "Drives & mechanisms",
 "year": null,
 "question": "Where can I get a 3D printable gear rack?",
 "tags": [
  "rack",
  "rack and pinion",
  "gear rack",
  "module 1",
  "mechanism",
  "motion",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "rack and pinion module 1",
  "gear rack stl",
  "3d printed rack and pinion"
 ],
 "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/gear-racks/",
 "sheet_txt": "https://xemstudio.com/objects/gear-racks/sheet.txt",
 "sheet": {
  "basis": "Involute rack, 20° pressure angle, module 1 and 2, matching the spur gears here",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Straight toothed bars that mesh with the module 1 and module 2 spur gears to turn rotation into straight-line travel.",
   "One turn of a z-tooth pinion moves the rack π × module × z: 62.8 mm for a 20-tooth module 1 gear.",
   "Module 1: 100 mm long, 8 × 8, three Ø3.4 mounting holes. Module 2: 150 mm long, 12 high × 10 wide."
  ],
  "table": {
   "columns": [
    "module",
    "length",
    "section",
    "travel per turn, 20 T pinion"
   ],
   "rows": [
    [
     "1",
     "100 mm",
     "8 × 8",
     "62.8 mm"
    ],
    [
     "2",
     "150 mm",
     "12 × 10",
     "125.7 mm"
    ]
   ]
  }
 },
 "sheet_text": "Gear racks: module 1 (100 mm) and module 2 (150 mm) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/gear-racks/  (CC BY 4.0)\nBasis: Involute rack, 20° pressure angle, module 1 and 2, matching the spur gears here\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Straight toothed bars that mesh with the module 1 and module 2 spur gears to turn rotation into straight-line travel.\n- One turn of a z-tooth pinion moves the rack π × module × z: 62.8 mm for a 20-tooth module 1 gear.\n- Module 1: 100 mm long, 8 × 8, three Ø3.4 mounting holes. Module 2: 150 mm long, 12 high × 10 wide.\n\nmodule  length  section  travel per turn, 20 T pinion\n1  100 mm  8 × 8  62.8 mm\n2  150 mm  12 × 10  125.7 mm\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Wikipedia: Rack and pinion — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Rack_and_pinion\n- Long Earth Society: Engine and rig builds on extrusion frames — 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/gear-racks/index.json\nAPI: https://xemstudio.com/api/geometry?object=gear-racks\n",
 "sources": [
  {
   "publisher": "Wikipedia",
   "title": "Rack and pinion",
   "url": "https://en.wikipedia.org/wiki/Rack_and_pinion",
   "formats": [
    "web"
   ],
   "license": "CC BY-SA 4.0 (text)",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Long Earth Society",
   "title": "Engine and rig builds on extrusion frames",
   "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": [
  "spur-gears-involute",
  "t-slot-extrusions",
  "mgn-linear-rails"
 ],
 "fits": [
  {
   "role": "Goes in or on",
   "items": [
    {
     "slug": "t-slot-extrusions",
     "why": "rack bolted along a frame"
    }
   ]
  },
  {
   "role": "Connects to",
   "items": [
    {
     "slug": "spur-gears-involute",
     "why": "module 1 / 2 pinion"
    }
   ]
  },
  {
   "role": "Alternatives",
   "items": [
    {
     "slug": "lead-screw-t8",
     "why": "screw drive instead of rack"
    }
   ]
  }
 ],
 "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": "mounting holes",
   "exact": "Ø3.4",
   "mates": "M3 screw clearance",
   "fit": "designed",
   "files": "rack-m"
  }
 ],
 "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": "Which gear meshes with these racks?",
   "a": "Any 20° module 1 or module 2 spur gear; the spur gear page has matching ones."
  },
  {
   "q": "How far does the rack move per turn?",
   "a": "Π × module × teeth: 62.8 mm for a 20-tooth module 1 pinion."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "rack-m1-100",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/gear-racks/rack-m1-100.step",
   "stl": "https://xemstudio.com/files/hardware/gear-racks/rack-m1-100.stl",
   "note": "rack, module 1, 100 mm, 8 high × 8 wide, three Ø3.4 mounting holes; meshes with the module 1 spur gears"
  },
  {
   "file": "rack-m2-150",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/gear-racks/rack-m2-150.step",
   "stl": "https://xemstudio.com/files/hardware/gear-racks/rack-m2-150.stl",
   "note": "rack, module 2, 150 mm, 12 high × 10 wide; meshes with the module 2 spur gears"
  }
 ],
 "markdown": "https://xemstudio.com/objects/gear-racks/index.md"
}