{
 "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": "pin-end-con-rods",
 "name": "Con-rods with Ø3 pin ends, 45 and 60 mm, 8 × 5",
 "kind": "hardware",
 "category": "Stirling engines",
 "group": "Drives & mechanisms",
 "year": null,
 "question": "What size con-rod connects a syringe piston to a crank?",
 "tags": [
  "con-rod",
  "connecting rod",
  "syringe",
  "alpha",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "syringe stirling con rod",
  "60 mm con rod 3 mm",
  "45 mm connecting rod stl",
  "con rod for syringe piston"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 3,
 "url": "https://xemstudio.com/objects/pin-end-con-rods/",
 "sheet_txt": "https://xemstudio.com/objects/pin-end-con-rods/sheet.txt",
 "sheet": {
  "basis": "Centres from the solved linkages (Ross yoke 60, alpha V-twin 60, can / LTD 45); Ø3 ends at the Ø3 pins; 5 thick for the syringe piston's 5 mm fork",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Plain con-rods whose Ø3 end holes turn on Ø3 pins (fit: run). All are 5 thick, the width of the syringe piston's fork slot, with 8 mm wide ends.",
   "Conrod-45: 45 mm centres, 53 × 8 × 5, for the can and coffee-cup engines.",
   "Conrod-60: 60 mm centres, 68 × 8 × 5, yoke corner to piston on the Ross yoke alpha.",
   "Alpha-conrod-60: 60 mm centres on Ø8 ends joined by a 6 wide web, for the alpha V-twin, where both rods share one crank pin and keep 0.8 mm from the syringe barrel wall over a full turn."
  ],
  "table": {
   "columns": [
    "file",
    "centres",
    "length",
    "end width",
    "thickness",
    "holes",
    "used on"
   ],
   "rows": [
    [
     "conrod-45",
     45,
     53,
     8,
     5,
     "Ø3",
     "can engine, LTD engine"
    ],
    [
     "conrod-60",
     60,
     68,
     8,
     5,
     "Ø3",
     "Ross yoke alpha"
    ],
    [
     "alpha-conrod-60",
     60,
     68,
     8,
     5,
     "Ø3",
     "alpha V-twin"
    ]
   ]
  }
 },
 "sheet_text": "Con-rods with Ø3 pin ends, 45 and 60 mm, 8 × 5 — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/pin-end-con-rods/  (CC BY 4.0)\nBasis: Centres from the solved linkages (Ross yoke 60, alpha V-twin 60, can / LTD 45); Ø3 ends at the Ø3 pins; 5 thick for the syringe piston's 5 mm fork\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Plain con-rods whose Ø3 end holes turn on Ø3 pins (fit: run). All are 5 thick, the width of the syringe piston's fork slot, with 8 mm wide ends.\n- Conrod-45: 45 mm centres, 53 × 8 × 5, for the can and coffee-cup engines.\n- Conrod-60: 60 mm centres, 68 × 8 × 5, yoke corner to piston on the Ross yoke alpha.\n- Alpha-conrod-60: 60 mm centres on Ø8 ends joined by a 6 wide web, for the alpha V-twin, where both rods share one crank pin and keep 0.8 mm from the syringe barrel wall over a full turn.\n\nfile  centres  length  end width  thickness  holes  used on\nconrod-45  45  53  8  5  Ø3  can engine, LTD engine\nconrod-60  60  68  8  5  Ø3  Ross yoke alpha\nalpha-conrod-60  60  68  8  5  Ø3  alpha V-twin\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Wikipedia: Ross yoke — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Ross_yoke\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, 3 parts): https://xemstudio.com/files/hardware/pin-end-con-rods/index.json\nAPI: https://xemstudio.com/api/geometry?object=pin-end-con-rods\n",
 "sources": [
  {
   "publisher": "Wikipedia",
   "title": "Ross yoke",
   "url": "https://en.wikipedia.org/wiki/Ross_yoke",
   "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": [
  "syringe-pistons",
  "ross-yoke",
  "alpha-v-twin-crank-disc",
  "can-engine-diaphragm",
  "crank-discs-5mm-bore"
 ],
 "fits": [
  {
   "role": "Connects to",
   "items": [
    {
     "slug": "syringe-pistons",
     "why": "small end in the piston's 5 mm fork on a Ø3 pin"
    },
    {
     "slug": "ross-yoke",
     "why": "conrod-60 on the yoke's corner pins"
    },
    {
     "slug": "alpha-v-twin-crank-disc",
     "why": "both alpha-conrod-60s on the one Ø3 crank pin"
    },
    {
     "slug": "rod-clevises",
     "why": "conrod-45 on the Ø3-bore crank discs"
    }
   ]
  },
  {
   "role": "Alternatives",
   "items": [
    {
     "slug": "crank-discs-5mm-bore",
     "why": "con-rods with 623 bearing ends"
    }
   ]
  },
  {
   "role": "Also needed",
   "items": [
    {
     "slug": "dowel-pins-metric",
     "why": "Ø3 pins"
    }
   ]
  }
 ],
 "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": "con-rod ends",
   "exact": "Ø3",
   "mates": "Ø3 pins (turn on them)",
   "fit": "run",
   "files": "alpha-conrod-"
  },
  {
   "feature": "con-rod ends",
   "exact": "Ø3",
   "mates": "Ø3 pins (turn on them)",
   "fit": "run",
   "files": "conrod-"
  }
 ],
 "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": "Why is the alpha V-twin con-rod 60 mm long?",
   "a": "A shorter rod swings further and touches the 14.5 mm barrel near its mouth; at 60 mm and 16 mm stroke it clears the wall by about 0.8 mm."
  },
  {
   "q": "How thick are these con-rods?",
   "a": "5 mm, the width of the 10 mL syringe piston's fork slot."
  },
  {
   "q": "What pins do the con-rods use?",
   "a": "Ø3 pins; the rod ends turn on them."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "conrod-60",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/ross-yoke-kit/conrod-60.step",
   "stl": "https://xemstudio.com/files/hardware/ross-yoke-kit/conrod-60.stl",
   "note": "con-rod 60 mm, 8 wide × 5, Ø3 ends (pins turn in them): yoke corner to the syringe piston's fork"
  },
  {
   "file": "conrod-45",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/ross-yoke-kit/conrod-45.step",
   "stl": "https://xemstudio.com/files/hardware/ross-yoke-kit/conrod-45.stl",
   "note": "con-rod 45 mm, Ø3 running ends, 8 wide × 5: plain-end rod for the can and coffee-cup engines' syringe pistons"
  },
  {
   "file": "alpha-conrod-60",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/alpha-v-twin-frame/alpha-conrod-60.step",
   "stl": "https://xemstudio.com/files/hardware/alpha-v-twin-frame/alpha-conrod-60.stl",
   "note": "con-rod 60 mm, 8 wide × 5, Ø3 plain ends (the pins turn in them; make two): small end in the syringe piston's 5 mm fork"
  }
 ],
 "markdown": "https://xemstudio.com/objects/pin-end-con-rods/index.md"
}