{
 "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": "hose-barbs",
 "name": "Hose barbs for 2, 3, 4, 6 and 8 mm ID tube",
 "kind": "hardware",
 "category": "Hardware",
 "group": "Pipe & fittings",
 "year": null,
 "question": "What barb size for 4 mm ID silicone tube?",
 "tags": [
  "barb",
  "hose barb",
  "fitting",
  "tube",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "hose barb size for 4mm tube",
  "hose barb dimensions",
  "barb fitting stl",
  "silicone tube barb",
  "3d print hose barb"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 5,
 "url": "https://xemstudio.com/objects/hose-barbs/",
 "sheet_txt": "https://xemstudio.com/objects/hose-barbs/sheet.txt",
 "sheet": {
  "basis": "Barb geometry rule: shank Ø = tube ID, three 2.5 mm ramps to tube ID + 1.2 (the designed stretch), hex base AF = ID + 6",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Each barb has a 14 mm shank at the tube ID, three ridges (at 2, 6 and 10 mm from the tip) that ramp over 2.5 mm from the ID to ID + 1.2, and a 4 mm hex base; overall 18 mm.",
   "Sizes: 2 mm (ridges Ø3.2, Ø1 bore, 8 AF), 3 mm (Ø4.2, Ø1.5, 9 AF), 4 mm (Ø5.2, Ø2.5, 10 AF), 6 mm (Ø7.2, Ø4.5, 12 AF), 8 mm (Ø9.2, Ø6.5, 14 AF).",
   "The +1.2 on the ridges is the designed stretch of the tube; the shank is the tube ID, exact.",
   "The can-engine cap's transfer port is an integral Ø4 barb with the same profile as barb-4mm."
  ],
  "table": {
   "columns": [
    "barb",
    "shank_mm",
    "ridge_mm",
    "bore_mm",
    "hex_af_mm"
   ],
   "rows": [
    [
     "barb-2mm",
     2,
     3.2,
     1,
     8
    ],
    [
     "barb-3mm",
     3,
     4.2,
     1.5,
     9
    ],
    [
     "barb-4mm",
     4,
     5.2,
     2.5,
     10
    ],
    [
     "barb-6mm",
     6,
     7.2,
     4.5,
     12
    ],
    [
     "barb-8mm",
     8,
     9.2,
     6.5,
     14
    ]
   ]
  }
 },
 "sheet_text": "Hose barbs for 2, 3, 4, 6 and 8 mm ID tube — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/hose-barbs/  (CC BY 4.0)\nBasis: Barb geometry rule: shank Ø = tube ID, three 2.5 mm ramps to tube ID + 1.2 (the designed stretch), hex base AF = ID + 6\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Each barb has a 14 mm shank at the tube ID, three ridges (at 2, 6 and 10 mm from the tip) that ramp over 2.5 mm from the ID to ID + 1.2, and a 4 mm hex base; overall 18 mm.\n- Sizes: 2 mm (ridges Ø3.2, Ø1 bore, 8 AF), 3 mm (Ø4.2, Ø1.5, 9 AF), 4 mm (Ø5.2, Ø2.5, 10 AF), 6 mm (Ø7.2, Ø4.5, 12 AF), 8 mm (Ø9.2, Ø6.5, 14 AF).\n- The +1.2 on the ridges is the designed stretch of the tube; the shank is the tube ID, exact.\n- The can-engine cap's transfer port is an integral Ø4 barb with the same profile as barb-4mm.\n\nbarb  shank_mm  ridge_mm  bore_mm  hex_af_mm\nbarb-2mm  2  3.2  1  8\nbarb-3mm  3  4.2  1.5  9\nbarb-4mm  4  5.2  2.5  10\nbarb-6mm  6  7.2  4.5  12\nbarb-8mm  8  9.2  6.5  14\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Wikipedia: Hose barb — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Hose_barb\n- Wikipedia: Push-fit fitting — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Push-to-connect_fitting\n- McMaster-Carr: Tubing (free STEP per part, for your own design use; no redistribution) — STEP, PDF — McMaster-Carr site terms [verify license at link] — https://www.mcmaster.com/products/tubing/\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, 5 parts): https://xemstudio.com/files/hardware/hose-barbs/index.json\nAPI: https://xemstudio.com/api/geometry?object=hose-barbs\n",
 "sources": [
  {
   "publisher": "Wikipedia",
   "title": "Hose barb",
   "url": "https://en.wikipedia.org/wiki/Hose_barb",
   "formats": [
    "web"
   ],
   "license": "CC BY-SA 4.0 (text)",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Wikipedia",
   "title": "Push-fit fitting",
   "url": "https://en.wikipedia.org/wiki/Push-to-connect_fitting",
   "formats": [
    "web"
   ],
   "license": "CC BY-SA 4.0 (text)",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "McMaster-Carr",
   "title": "Tubing (free STEP per part, for your own design use; no redistribution)",
   "url": "https://www.mcmaster.com/products/tubing/",
   "formats": [
    "STEP",
    "PDF"
   ],
   "license": "McMaster-Carr site terms",
   "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": [
  "silicone-tube",
  "push-fit-fittings",
  "can-engine-cap",
  "zip-ties"
 ],
 "fits": [
  {
   "role": "Goes in or on",
   "items": [
    {
     "slug": "can-engine-cap",
     "why": "the cap's integral Ø4 barb uses this profile"
    }
   ]
  },
  {
   "role": "Connects to",
   "items": [
    {
     "slug": "silicone-tube",
     "why": "tube ID over the shank, stretched over the ID + 1.2 ridges"
    }
   ]
  },
  {
   "role": "Alternatives",
   "items": [
    {
     "slug": "push-fit-fittings",
     "why": "for stiff PU tube"
    }
   ]
  },
  {
   "role": "Also needed",
   "items": [
    {
     "slug": "zip-ties",
     "why": "clamp over the tube on the barb"
    }
   ]
  }
 ],
 "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": "barb shank",
   "exact": "Ø = tube ID (2 / 3 / 4 / 6 / 8)",
   "mates": "silicone tube ID",
   "fit": "designed",
   "files": "barb-"
  },
  {
   "feature": "barb ridges",
   "exact": "tube ID + 1.2",
   "mates": "silicone tube (stretched)",
   "fit": "designed",
   "files": "barb-"
  }
 ],
 "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 barb size for 6 mm ID silicone tube?",
   "a": "A Ø6 shank with ridges to Ø7.2 (ID + 1.2), three ridges 2.5 mm long; that is barb-6mm."
  },
  {
   "q": "How long is the barb?",
   "a": "18 mm overall: a 14 mm barbed shank plus a 4 mm hex base."
  },
  {
   "q": "What is the bore of the 4 mm barb?",
   "a": "Ø2.5 through, with ridges to Ø5.2 and a 10 mm AF hex."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "barb-2mm",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/silicone-tube-and-fittings/barb-2mm.step",
   "stl": "https://xemstudio.com/files/hardware/silicone-tube-and-fittings/barb-2mm.stl",
   "note": "hose barb for 2 mm ID tube: Ø2 shank, three barbs to Ø3.2, Ø1 bore, 8 AF hex base"
  },
  {
   "file": "barb-3mm",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/silicone-tube-and-fittings/barb-3mm.step",
   "stl": "https://xemstudio.com/files/hardware/silicone-tube-and-fittings/barb-3mm.stl",
   "note": "hose barb for 3 mm ID tube: Ø3 shank, three barbs to Ø4.2, Ø1.5 bore, 9 AF hex base"
  },
  {
   "file": "barb-4mm",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/silicone-tube-and-fittings/barb-4mm.step",
   "stl": "https://xemstudio.com/files/hardware/silicone-tube-and-fittings/barb-4mm.stl",
   "note": "hose barb for 4 mm ID tube: Ø4 shank, three barbs to Ø5.2, Ø2.5 bore, 10 AF hex base"
  },
  {
   "file": "barb-6mm",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/silicone-tube-and-fittings/barb-6mm.step",
   "stl": "https://xemstudio.com/files/hardware/silicone-tube-and-fittings/barb-6mm.stl",
   "note": "hose barb for 6 mm ID tube: Ø6 shank, three barbs to Ø7.2, Ø4.5 bore, 12 AF hex base"
  },
  {
   "file": "barb-8mm",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/silicone-tube-and-fittings/barb-8mm.step",
   "stl": "https://xemstudio.com/files/hardware/silicone-tube-and-fittings/barb-8mm.stl",
   "note": "hose barb for 8 mm ID tube: Ø8 shank, three barbs to Ø9.2, Ø6.5 bore, 14 AF hex base"
  }
 ],
 "markdown": "https://xemstudio.com/objects/hose-barbs/index.md"
}