{ "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": "wrist-pin-3x16", "name": "Wrist pin Ø3 × 16", "kind": "hardware", "category": "Stirling engines", "group": "Drives & mechanisms", "year": null, "question": "What size wrist pin goes in a small Stirling piston or crosshead?", "tags": [ "wrist pin", "pin", "stirling", "long earth society" ], "aliases": [ "wrist pin 3mm", "3 x 16 pin", "gudgeon pin 3mm" ], "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/wrist-pin-3x16/", "sheet_txt": "https://xemstudio.com/objects/wrist-pin-3x16/sheet.txt", "sheet": { "basis": "Ø3 at the piston boss and crosshead holes (fit: press); 0.4 chamfer both ends", "overall_mm": { "length": null, "width": null, "height": null }, "notes": [ "A Ø3 × 16 pin, 0.4 mm chamfer on both ends.", "It presses into the power piston's wrist-pin boss or through the crosshead's cheeks (fit: press); the con-rod end turns on it." ], "table": { "columns": [ "parameter", "value" ], "rows": [ [ "diameter", 3 ], [ "length", 16 ], [ "chamfers", "0.4 both ends" ] ] } }, "sheet_text": "Wrist pin Ø3 × 16 — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/wrist-pin-3x16/ (CC BY 4.0)\nBasis: Ø3 at the piston boss and crosshead holes (fit: press); 0.4 chamfer both ends\nCatalog version: 2026-10-20\n\nSizes: see table below\n- A Ø3 × 16 pin, 0.4 mm chamfer on both ends.\n- It presses into the power piston's wrist-pin boss or through the crosshead's cheeks (fit: press); the con-rod end turns on it.\n\nparameter value\ndiameter 3\nlength 16\nchamfers 0.4 both ends\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Wikipedia: Crosshead — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Crosshead\n- Wikipedia: Piston — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Piston\n- James R. Senft: Miniature Stirling engine piston fits (LTD book) — book — reference [verify license at link] — https://www.stirlingengine.com/\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/wrist-pin-3x16/index.json\nAPI: https://xemstudio.com/api/geometry?object=wrist-pin-3x16\n", "sources": [ { "publisher": "Wikipedia", "title": "Crosshead", "url": "https://en.wikipedia.org/wiki/Crosshead", "formats": [ "web" ], "license": "CC BY-SA 4.0 (text)", "license_verified": true, "hosted": false }, { "publisher": "Wikipedia", "title": "Piston", "url": "https://en.wikipedia.org/wiki/Piston", "formats": [ "web" ], "license": "CC BY-SA 4.0 (text)", "license_verified": true, "hosted": false }, { "publisher": "James R. Senft", "title": "Miniature Stirling engine piston fits (LTD book)", "url": "https://www.stirlingengine.com/", "formats": [ "book" ], "license": "reference", "license_verified": false, "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": [ "power-piston", "crosshead-8mm", "dowel-pins-metric" ], "fits": [ { "role": "Goes in or on", "items": [ { "slug": "power-piston", "why": "in the wrist-pin boss" }, { "slug": "crosshead-8mm", "why": "through the clevis cheeks" } ] }, { "role": "Alternatives", "items": [ { "slug": "dowel-pins-metric", "why": "Ø3 × 16 dowel" } ] } ], "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": "wrist pin", "exact": "Ø3", "mates": "piston boss / crosshead clevis", "fit": "press", "files": "wrist-pin-" } ], "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 wrist pin fits the power piston?", "a": "Ø3 × 16, pressed in the Ø3 boss hole." }, { "q": "Can a stock dowel be used?", "a": "Any Ø3 × 16 pin is the same size; dowel-pins-metric lists Ø3 × 16." } ], "files_license": null, "offers": [ { "file": "wrist-pin-3x16", "formats": [ "step", "stl" ], "price_usd": 0, "license": "CC BY 4.0 (Xem Studio)", "step": "https://xemstudio.com/files/hardware/power-cylinder-piston-crosshead/wrist-pin-3x16.step", "stl": "https://xemstudio.com/files/hardware/power-cylinder-piston-crosshead/wrist-pin-3x16.stl", "note": "Ø3 × 16 wrist pin (dowel) for the piston boss" } ], "markdown": "https://xemstudio.com/objects/wrist-pin-3x16/index.md" }