{
 "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": "ross-yoke-frame",
 "name": "Ross yoke alpha frame for two 10 mL syringes",
 "kind": "hardware",
 "category": "Stirling engines",
 "group": "Drives & mechanisms",
 "year": null,
 "question": "What frame holds two parallel syringes and a crank for a Ross yoke Stirling engine?",
 "tags": [
  "ross yoke",
  "frame",
  "alpha",
  "syringe",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "ross yoke frame",
  "two syringe stirling frame",
  "parallel cylinder alpha frame stl"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 1,
 "url": "https://xemstudio.com/objects/ross-yoke-frame/",
 "sheet_txt": "https://xemstudio.com/objects/ross-yoke-frame/sheet.txt",
 "sheet": {
  "basis": "Solved Ross linkage: barrel axes 40 apart, socket inner faces 63 above the crank axis, rocking-link post at (−40, 20); 625 pockets at the bearing OD",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "The one-piece frame of the Ross yoke alpha: 83 × 53.45 × 148. A Ø24 boss carries the Ø5 crankshaft in two 625 bearings (Ø16 pockets, fit: press) with a Ø5.6 passage between them.",
   "Two Ø15.9 barrel sockets (fit: socket) on parallel axes 40 mm apart; their inner faces sit 63 mm above the crank axis, where the syringe finger flanges seat. The lowest piston skirt comes to 62.1 mm, so the pistons never leave the barrels; M3 pinch screws in Ø2.5 holes.",
   "A post at (−40, 20) has a Ø3 hole (fit: press) for the rocking-link pin. The foot has 2 × Ø5.5 at 50 mm for M5 into a 2020 rail."
  ],
  "table": {
   "columns": [
    "parameter",
    "value"
   ],
   "rows": [
    [
     "outline",
     "83 × 53.45 × 148"
    ],
    [
     "barrel sockets",
     "2 × Ø15.9, axes 40 apart"
    ],
    [
     "socket inner face",
     "63 above crank axis"
    ],
    [
     "bearing pockets",
     "2 × Ø16 (625)"
    ],
    [
     "rocking-link post",
     "Ø3 at (−40, 20)"
    ],
    [
     "foot",
     "2 × Ø5.5 at 50"
    ]
   ]
  }
 },
 "sheet_text": "Ross yoke alpha frame for two 10 mL syringes — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/ross-yoke-frame/  (CC BY 4.0)\nBasis: Solved Ross linkage: barrel axes 40 apart, socket inner faces 63 above the crank axis, rocking-link post at (−40, 20); 625 pockets at the bearing OD\nCatalog version: 2026-10-20\n\nSizes: see table below\n- The one-piece frame of the Ross yoke alpha: 83 × 53.45 × 148. A Ø24 boss carries the Ø5 crankshaft in two 625 bearings (Ø16 pockets, fit: press) with a Ø5.6 passage between them.\n- Two Ø15.9 barrel sockets (fit: socket) on parallel axes 40 mm apart; their inner faces sit 63 mm above the crank axis, where the syringe finger flanges seat. The lowest piston skirt comes to 62.1 mm, so the pistons never leave the barrels; M3 pinch screws in Ø2.5 holes.\n- A post at (−40, 20) has a Ø3 hole (fit: press) for the rocking-link pin. The foot has 2 × Ø5.5 at 50 mm for M5 into a 2020 rail.\n\nparameter  value\noutline  83 × 53.45 × 148\nbarrel sockets  2 × Ø15.9, axes 40 apart\nsocket inner face  63 above crank axis\nbearing pockets  2 × Ø16 (625)\nrocking-link post  Ø3 at (−40, 20)\nfoot  2 × Ø5.5 at 50\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, 1 parts): https://xemstudio.com/files/hardware/ross-yoke-frame/index.json\nAPI: https://xemstudio.com/api/geometry?object=ross-yoke-frame\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": [
  "ross-yoke",
  "ross-crank-disc",
  "ross-rocking-link",
  "plastic-syringes",
  "t-slot-extrusions",
  "list-ross-yoke-alpha"
 ],
 "fits": [
  {
   "role": "Parts that fit it",
   "items": [
    {
     "slug": "transfer-tee-4mm",
     "why": "between the Ross alpha's syringe tips"
    }
   ]
  },
  {
   "role": "Goes in or on",
   "items": [
    {
     "slug": "plastic-syringes",
     "why": "two 10 mL barrels in the Ø15.9 sockets"
    },
    {
     "slug": "t-slot-extrusions",
     "why": "2 × M5 into 2020"
    }
   ]
  },
  {
   "role": "Connects to",
   "items": [
    {
     "slug": "ross-rocking-link",
     "why": "Ø3 × 20 pin in the post"
    },
    {
     "slug": "ross-crank-disc",
     "why": "on the Ø5 shaft in the boss"
    }
   ]
  },
  {
   "role": "Alternatives",
   "items": [
    {
     "slug": "alpha-v-twin-syringe-frame",
     "why": "V-twin alpha on one crank pin"
    }
   ]
  },
  {
   "role": "Also needed",
   "items": [
    {
     "slug": "ball-bearings-metric",
     "why": "2 × 625"
    }
   ]
  }
 ],
 "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": "barrel sockets",
   "exact": "Ø15.9",
   "mates": "10 mL syringe barrel",
   "fit": "socket",
   "files": "ross-frame-"
  },
  {
   "feature": "bearing pockets",
   "exact": "Ø16",
   "mates": "625 bearing",
   "fit": "press",
   "files": "ross-frame-"
  },
  {
   "feature": "frame-post pin hole",
   "exact": "Ø3",
   "mates": "Ø3 × 20 pin",
   "fit": "press",
   "files": "ross-frame-"
  },
  {
   "feature": "shaft passage between pockets",
   "exact": "Ø5.6",
   "mates": "Ø5 shaft (no contact)",
   "fit": "designed",
   "files": "ross-frame-"
  },
  {
   "feature": "pinch-screw holes",
   "exact": "Ø2.5",
   "mates": "M3 tap drill",
   "fit": "designed",
   "files": "ross-frame-"
  },
  {
   "feature": "foot holes",
   "exact": "Ø5.5",
   "mates": "M5 clearance (ISO 273)",
   "fit": "designed",
   "files": "ross-frame-"
  }
 ],
 "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": "How far apart are the syringes on the Ross yoke frame?",
   "a": "40 mm between parallel axes; turn both finger flanges front-to-back so they do not touch."
  },
  {
   "q": "How does the Ross frame mount?",
   "a": "Two M5 screws through the Ø5.5 foot holes, 50 mm apart, into 2020 extrusion."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "ross-frame-2x-10ml",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/ross-yoke-kit/ross-frame-2x-10ml.step",
   "stl": "https://xemstudio.com/files/hardware/ross-yoke-kit/ross-frame-2x-10ml.stl",
   "note": "Ross alpha frame: Ø5 shaft in two 625s, two 10 mL barrel sockets on parallel axes 2 × 20 = 40 mm apart (inner faces 63 mm above the crank axis), rocking-link post at (-40, 20), foot 2 × M5 at 50 mm for 2020"
  }
 ],
 "markdown": "https://xemstudio.com/objects/ross-yoke-frame/index.md"
}