{ "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-crank-disc", "name": "Ross yoke crank disc Ø24, 6 mm throw", "kind": "hardware", "category": "Stirling engines", "group": "Drives & mechanisms", "year": null, "question": "What crank disc drives a Ross yoke?", "tags": [ "ross yoke", "crank disc", "stirling", "long earth society" ], "aliases": [ "ross yoke crank", "6 mm throw crank disc", "crank disc 5 mm bore" ], "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-crank-disc/", "sheet_txt": "https://xemstudio.com/objects/ross-crank-disc/sheet.txt", "sheet": { "basis": "Solved Ross linkage: crank throw e = 6", "overall_mm": { "length": null, "width": null, "height": null }, "notes": [ "The crank that drives the Ross yoke: Ø24 × 6, Ø5 bore (fit: slide) for the crankshaft, Ø2.5 radial hole (M3 tap size) for the grub screw.", "One Ø3 hole (fit: press) at 6 mm takes a Ø3 × 20 crank pin; the yoke's bottom vertex rides on it, and a 3 mm collar holds it on." ], "table": { "columns": [ "parameter", "value" ], "rows": [ [ "disc", "Ø24 × 6" ], [ "bore", "Ø5" ], [ "throw", 6 ], [ "pin hole", "Ø3" ], [ "grub hole", "Ø2.5" ] ] } }, "sheet_text": "Ross yoke crank disc Ø24, 6 mm throw — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/ross-crank-disc/ (CC BY 4.0)\nBasis: Solved Ross linkage: crank throw e = 6\nCatalog version: 2026-10-20\n\nSizes: see table below\n- The crank that drives the Ross yoke: Ø24 × 6, Ø5 bore (fit: slide) for the crankshaft, Ø2.5 radial hole (M3 tap size) for the grub screw.\n- One Ø3 hole (fit: press) at 6 mm takes a Ø3 × 20 crank pin; the yoke's bottom vertex rides on it, and a 3 mm collar holds it on.\n\nparameter value\ndisc Ø24 × 6\nbore Ø5\nthrow 6\npin hole Ø3\ngrub hole Ø2.5\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-crank-disc/index.json\nAPI: https://xemstudio.com/api/geometry?object=ross-crank-disc\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-yoke-frame", "stirling-crankshafts", "list-ross-yoke-alpha" ], "fits": [ { "role": "Goes in or on", "items": [ { "slug": "ross-yoke-frame", "why": "on the shaft beside the boss" } ] }, { "role": "Connects to", "items": [ { "slug": "ross-yoke", "why": "yoke's bottom vertex on the Ø3 pin" }, { "slug": "stirling-crankshafts", "why": "Ø5 × 80 crankshaft, Ø3 × 20 pin" } ] }, { "role": "Also needed", "items": [ { "slug": "set-screws-metric", "why": "M3 grub" } ] } ], "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": "crank-disc bore", "exact": "Ø5", "mates": "Ø5 crankshaft (M3 grub)", "fit": "slide", "files": "ross-crank-disc-" }, { "feature": "crank-disc pin hole", "exact": "Ø3", "mates": "Ø3 crank pin", "fit": "press", "files": "ross-crank-disc-" } ], "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 throw does the Ross yoke crank have?", "a": "6 mm; with a = h = 20 it gives piston strokes of 17.0 and 17.2 mm." }, { "q": "How is the Ross crank disc fixed to the shaft?", "a": "An M3 grub in the Ø2.5 radial hole onto the Ø5 shaft's D-flat." } ], "files_license": null, "offers": [ { "file": "ross-crank-disc-e6", "formats": [ "step", "stl" ], "price_usd": 0, "license": "CC BY 4.0 (Xem Studio)", "step": "https://xemstudio.com/files/hardware/ross-yoke-kit/ross-crank-disc-e6.step", "stl": "https://xemstudio.com/files/hardware/ross-yoke-kit/ross-crank-disc-e6.stl", "note": "crank disc Ø24 × 6, Ø5 bore, Ø2.5 tap-drill hole for an M3 grub, Ø3 pin at 6 mm (the yoke rides on it)" } ], "markdown": "https://xemstudio.com/objects/ross-crank-disc/index.md" }