{
 "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": "e-clip-grooved-rods-5mm",
 "name": "Ø5 rods with E-clip grooves, 120 and 150 mm",
 "kind": "hardware",
 "category": "Stirling engines",
 "group": "Free-piston",
 "year": null,
 "question": "What size rod with E-clip grooves carries a free-piston Stirling piston or displacer?",
 "tags": [
  "rod",
  "e-clip",
  "free piston",
  "shaft",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "5mm rod e clip groove",
  "free piston stirling rod",
  "displacer rod 5mm",
  "piston rod 5 x 120"
 ],
 "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/e-clip-grooved-rods-5mm/",
 "sheet_txt": "https://xemstudio.com/objects/e-clip-grooved-rods-5mm/sheet.txt",
 "sheet": {
  "basis": "Ø5 rod; DIN 6799 E-clip groove for Ø5 (Ø4.0 × 0.7), 10 mm from each end",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Plain Ø5 rods with two DIN 6799 E-clip grooves, Ø4.0 × 0.7 wide, 10 mm from each end; 0.5 mm chamfer on one end.",
   "Piston-rod-5x120-grooved (Ø5 × 120) carries the free-piston core's power piston and the linear alternator mover; displacer-rod-5x150-grooved (Ø5 × 150) carries the displacer.",
   "The parts on them have Ø5 bores (fit: slide); E-clips in the grooves locate them."
  ],
  "table": {
   "columns": [
    "file",
    "diameter",
    "length",
    "grooves",
    "groove from ends"
   ],
   "rows": [
    [
     "piston-rod-5x120-grooved",
     5,
     120,
     "2 × Ø4.0 × 0.7",
     10
    ],
    [
     "displacer-rod-5x150-grooved",
     5,
     150,
     "2 × Ø4.0 × 0.7",
     10
    ]
   ]
  }
 },
 "sheet_text": "Ø5 rods with E-clip grooves, 120 and 150 mm — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/e-clip-grooved-rods-5mm/  (CC BY 4.0)\nBasis: Ø5 rod; DIN 6799 E-clip groove for Ø5 (Ø4.0 × 0.7), 10 mm from each end\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Plain Ø5 rods with two DIN 6799 E-clip grooves, Ø4.0 × 0.7 wide, 10 mm from each end; 0.5 mm chamfer on one end.\n- Piston-rod-5x120-grooved (Ø5 × 120) carries the free-piston core's power piston and the linear alternator mover; displacer-rod-5x150-grooved (Ø5 × 150) carries the displacer.\n- The parts on them have Ø5 bores (fit: slide); E-clips in the grooves locate them.\n\nfile  diameter  length  grooves  groove from ends\npiston-rod-5x120-grooved  5  120  2 × Ø4.0 × 0.7  10\ndisplacer-rod-5x150-grooved  5  150  2 × Ø4.0 × 0.7  10\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- NASA (NTRS, public domain): Linear alternator design for free-piston Stirling convertors (2005) — PDF — US Government work, public domain — https://ntrs.nasa.gov/search?q=20050182934\n- NASA (NTRS, public domain): Sunpower/NASA 80 We free-piston Stirling convertor (2002) — PDF — US Government work, public domain — https://ntrs.nasa.gov/search?q=20020047256\n- Wikipedia: Linear alternator — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Linear_alternator\n- Wikipedia: Free-piston engine — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Free-piston_engine\n- Long Earth Society: Engine 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/e-clip-grooved-rods-5mm/index.json\nAPI: https://xemstudio.com/api/geometry?object=e-clip-grooved-rods-5mm\n",
 "sources": [
  {
   "publisher": "NASA (NTRS, public domain)",
   "title": "Linear alternator design for free-piston Stirling convertors (2005)",
   "url": "https://ntrs.nasa.gov/search?q=20050182934",
   "formats": [
    "PDF"
   ],
   "license": "US Government work, public domain",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "NASA (NTRS, public domain)",
   "title": "Sunpower/NASA 80 We free-piston Stirling convertor (2002)",
   "url": "https://ntrs.nasa.gov/search?q=20020047256",
   "formats": [
    "PDF"
   ],
   "license": "US Government work, public domain",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Wikipedia",
   "title": "Linear alternator",
   "url": "https://en.wikipedia.org/wiki/Linear_alternator",
   "formats": [
    "web"
   ],
   "license": "CC BY-SA 4.0 (text)",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Wikipedia",
   "title": "Free-piston engine",
   "url": "https://en.wikipedia.org/wiki/Free-piston_engine",
   "formats": [
    "web"
   ],
   "license": "CC BY-SA 4.0 (text)",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Long Earth Society",
   "title": "Engine 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": [
  "free-piston-displacer",
  "free-piston-power-piston",
  "linear-alternator-mover",
  "metric-shafts",
  "stirling-crankshafts"
 ],
 "fits": [
  {
   "role": "Connects to",
   "items": [
    {
     "slug": "free-piston-power-piston",
     "why": "Ø5 rod in the piston's bore"
    },
    {
     "slug": "free-piston-displacer",
     "why": "Ø5 rod in the displacer's boss"
    },
    {
     "slug": "linear-alternator-mover",
     "why": "mover clamps the Ø5 rod"
    },
    {
     "slug": "gas-spring-piston",
     "why": "Ø5 bore on the rod"
    }
   ]
  },
  {
   "role": "Alternatives",
   "items": [
    {
     "slug": "stirling-crankshafts",
     "why": "other Ø5 rods and tubes"
    }
   ]
  },
  {
   "role": "Also needed",
   "items": [
    {
     "slug": "metric-shafts",
     "why": "eclip-5mm in the grooves"
    }
   ]
  }
 ],
 "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": "rod E-clip grooves",
   "exact": "Ø4.0 × 0.7",
   "mates": "DIN 6799 E-clip for Ø5",
   "fit": "designed",
   "files": "piston-rod-"
  },
  {
   "feature": "rod bores",
   "exact": "Ø5",
   "mates": "Ø5 rod",
   "fit": "slide",
   "files": "all"
  },
  {
   "feature": "displacer in the liner",
   "exact": "liner bore − 1.0 (0.5 radial)",
   "mates": "cylinder liner bore",
   "fit": "designed",
   "files": "displacer-"
  },
  {
   "feature": "rod E-clip grooves",
   "exact": "Ø4.0 × 0.7",
   "mates": "DIN 6799 E-clip for Ø5",
   "fit": "designed",
   "files": "displacer-rod-"
  }
 ],
 "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 E-clip fits a 5 mm rod?",
   "a": "DIN 6799 for Ø5: groove Ø4.0 × 0.7, as cut 10 mm from each end of these rods."
  },
  {
   "q": "Which rod is the displacer rod?",
   "a": "The 150 mm one; the 120 mm rod is the power piston rod."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "piston-rod-5x120-grooved",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/linear-alternator-kit/piston-rod-5x120-grooved.step",
   "stl": "https://xemstudio.com/files/hardware/linear-alternator-kit/piston-rod-5x120-grooved.stl",
   "note": "Ø5 × 120 piston rod with two DIN 6799 E-clip grooves Ø4.0 × 0.7, 10 mm from each end (free-piston core version; the tri-clamp kit uses the 5 mm tube)"
  },
  {
   "file": "displacer-rod-5x150-grooved",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/free-piston-core/displacer-rod-5x150-grooved.step",
   "stl": "https://xemstudio.com/files/hardware/free-piston-core/displacer-rod-5x150-grooved.stl",
   "note": "Ø5 × 150 displacer rod with two DIN 6799 E-clip grooves Ø4.0 × 0.7, 10 mm from each end"
  }
 ],
 "markdown": "https://xemstudio.com/objects/e-clip-grooved-rods-5mm/index.md"
}