{
 "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": "steel-and-airsoft-bbs",
 "name": "BBs: steel Ø4.5 mm (.177) and airsoft Ø6.0 mm",
 "kind": "standard",
 "category": "Hardware",
 "group": "Found & household materials",
 "year": null,
 "question": "What diameter is a BB and an airsoft BB?",
 "tags": [
  "bb",
  "airsoft",
  "ball",
  "sphere",
  "found materials",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "bb diameter mm",
  "airsoft bb size",
  "177 bb diameter",
  "6mm bb",
  "bb as bearing ball"
 ],
 "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/steel-and-airsoft-bbs/",
 "sheet_txt": "https://xemstudio.com/objects/steel-and-airsoft-bbs/sheet.txt",
 "sheet": {
  "basis": "Steel BB .177 calibre (Ø4.5); airsoft 6 mm BB (5.95 ±0.01); drawn as true spheres",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "A steel BB is Ø4.5 mm (.177 calibre); the file is a Ø4.5 sphere.",
   "An airsoft BB is nominally Ø6.0 mm, typically 5.95 ±0.01 mm; the file is a Ø6.0 sphere.",
   "Airsoft BBs are round enough to act as 6 mm balls in a race with a Ø6.0 groove under light load.",
   "On the can engine I use BBs as low-friction guides for the displacer rod."
  ],
  "table": {
   "columns": [
    "ball",
    "dia_mm",
    "note"
   ],
   "rows": [
    [
     "steel BB",
     4.5,
     ".177 cal"
    ],
    [
     "airsoft BB",
     6,
     "5.95 ±0.01 typical"
    ]
   ]
  }
 },
 "sheet_text": "BBs: steel Ø4.5 mm (.177) and airsoft Ø6.0 mm — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/steel-and-airsoft-bbs/  (CC BY 4.0)\nBasis: Steel BB .177 calibre (Ø4.5); airsoft 6 mm BB (5.95 ±0.01); drawn as true spheres\nCatalog version: 2026-10-20\n\nSizes: see table below\n- A steel BB is Ø4.5 mm (.177 calibre); the file is a Ø4.5 sphere.\n- An airsoft BB is nominally Ø6.0 mm, typically 5.95 ±0.01 mm; the file is a Ø6.0 sphere.\n- Airsoft BBs are round enough to act as 6 mm balls in a race with a Ø6.0 groove under light load.\n- On the can engine I use BBs as low-friction guides for the displacer rod.\n\nball  dia_mm  note\nsteel BB  4.5  .177 cal\nairsoft BB  6.0  5.95 ±0.01 typical\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Wikipedia: Craft stick — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Craft_stick\n- Wikipedia: BB gun — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/BB_gun\n- Wikipedia: Table tennis — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Table_tennis\n- Long Earth Society: Engine builds (videos and write-ups) — 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/steel-and-airsoft-bbs/index.json\nAPI: https://xemstudio.com/api/geometry?object=steel-and-airsoft-bbs\n",
 "sources": [
  {
   "publisher": "Wikipedia",
   "title": "Craft stick",
   "url": "https://en.wikipedia.org/wiki/Craft_stick",
   "formats": [
    "web"
   ],
   "license": "CC BY-SA 4.0 (text)",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Wikipedia",
   "title": "BB gun",
   "url": "https://en.wikipedia.org/wiki/BB_gun",
   "formats": [
    "web"
   ],
   "license": "CC BY-SA 4.0 (text)",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Wikipedia",
   "title": "Table tennis",
   "url": "https://en.wikipedia.org/wiki/Table_tennis",
   "formats": [
    "web"
   ],
   "license": "CC BY-SA 4.0 (text)",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Long Earth Society",
   "title": "Engine builds (videos and write-ups)",
   "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": [
  "glass-marbles",
  "ping-pong-ball",
  "ball-bearings-metric",
  "can-engine-cap"
 ],
 "fits": [
  {
   "role": "Goes in or on",
   "items": [
    {
     "slug": "can-engine-cap",
     "why": "BBs as guides along the displacer rod"
    }
   ]
  },
  {
   "role": "Alternatives",
   "items": [
    {
     "slug": "ball-bearings-metric",
     "why": "a ball bearing where a race of loose balls is not enough"
    },
    {
     "slug": "glass-marbles",
     "why": "larger loose balls (Ø16)"
    }
   ]
  }
 ],
 "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": "What diameter is a steel BB?",
   "a": "4.5 mm (.177 calibre)."
  },
  {
   "q": "What size is an airsoft BB?",
   "a": "6 mm nominal, typically 5.95 ±0.01 mm."
  },
  {
   "q": "Can airsoft BBs be used as bearing balls?",
   "a": "For light loads, yes: they are 5.95 ±0.01 mm, so a race groove drawn at Ø6.0 holds them."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "steel-bb-4-5mm",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/sticks-skewers-wire-bbs/steel-bb-4-5mm.step",
   "stl": "https://xemstudio.com/files/hardware/sticks-skewers-wire-bbs/steel-bb-4-5mm.stl",
   "note": "steel BB Ø4.5 (.177 cal)"
  },
  {
   "file": "airsoft-bb-6mm",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/sticks-skewers-wire-bbs/airsoft-bb-6mm.step",
   "stl": "https://xemstudio.com/files/hardware/sticks-skewers-wire-bbs/airsoft-bb-6mm.stl",
   "note": "airsoft BB Ø6.0 (5.95)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/steel-and-airsoft-bbs/index.md"
}