{
 "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": "tri-clamp-power-pistons",
 "name": "Tri-clamp power pistons and crank linkage: full-bore ring-less pistons, con-rods, crank webs and a clamp-on crank frame for 1.5, 2 and 3 in spools",
 "kind": "hardware",
 "category": "Stirling engines",
 "group": "Tri-clamp engine parts",
 "year": null,
 "question": "What clearance does a ring-less Stirling power piston need in a 2 inch tri-clamp spool, and how do I get it?",
 "tags": [
  "piston",
  "power piston",
  "tri-clamp",
  "stirling",
  "beta",
  "alpha",
  "long earth society",
  "lapping",
  "crankshaft",
  "con-rod",
  "crank frame"
 ],
 "aliases": [
  "piston for 2 inch tri clamp spool",
  "tri clamp stirling crankshaft frame",
  "how to connect a piston to a crankshaft stirling",
  "stirling power piston no o-ring",
  "ring-less piston clearance",
  "lapped piston stl",
  "air piston tri clamp"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 30,
 "url": "https://xemstudio.com/objects/tri-clamp-power-pistons/",
 "sheet_txt": "https://xemstudio.com/objects/tri-clamp-power-pistons/sheet.txt",
 "sheet": {
  "basis": "16 ga ASME BPE tube bores (1.5 in = 34.8 mm, 2 in = 47.5, 3 in = 72.9); finished ring-less piston fit 0.02–0.05 mm diametral (graphite-in-glass and lapped-aluminium Stirling practice); FDM print-and-lap offsets from the Xem Studio calibration coupons",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "A Stirling power piston has no ring and no O-ring: the seal is the fit. Finished diametral clearance 0.02–0.05 mm; the test is that the piston falls slowly through the spool under its own weight with the far end open and holds for several seconds with it closed.",
   "You cannot print that fit. Print the closest offset your printer makes (f010/f020/f030 = 0.10/0.20/0.30 mm under bore after the hole/pin coupons have set your slicer), or the 'lap' version 0.10 mm over, then lap it in: 800 → 1500 grit wet, then metal polish, turning the piston in the actual spool on the lapping handle. PETG laps well; PLA galls. Finish with a dry graphite rub (pencil) and run it dry; oil adds friction and stiction in a Stirling.",
   "Length 1.2 × bore keeps it from cocking: the two 8 mm lands at the ends carry the fit; the 0.4 mm relief between them halves the rubbing area and traps dust. Wrist pin Ø3 (dowel-pins-metric) at 0.42 L, con-rod small end with a 623 bearing from the crank kit; the skirt is open so the rod swings inside it.",
   "Where it goes: beta engine (piston and displacer in one spool, displacer rod through the piston's wrist-pin gap), alpha (two spools at 90°, a piston in each, no displacer), or a big low-compression gamma (same-bore power cylinder: 1:1 swept ratio, suits an LTD on a hot plate). For a high-ratio gamma use the Ø20 piston from the power-cylinder entry instead.",
   "The -rod variants (f020 and lap) have a Ø5 crown boss for a dry 3 × 5 × 6 bushing (graphite-bronze, PTFE, or sintered bronze degreased in acetone; no oil) so a Ø3 displacer rod runs through the piston on a clearance fit: that is the beta / rhombic / free-piston piston. The piston plug in the tri-clamp linkage kit drops into the skirt, is retained by the two wrist-pin dowels, and carries the 5 mm tube piston rod with the displacer rod inside it.",
   "Mass: the 2 in piston prints at ~21 g in PETG (16.8 cm³); keep it light, it is the moving mass the flywheel has to swing.",
   "Linkage, designed so nothing else is needed: the crank frame is an ISO 2852 cap with a con-rod window and two bearing towers, so a stock clamp holds it on the spool's open ferrule; a Ø8 shaft (shafts entry, 80–100 mm) runs in two 608s; two crank webs (Ø8 bore, M3 grub) carry a Ø3 pin at stroke/2 between them; the con-rod runs on 623s at both ends. Order along the shaft: tower · web · rod · web · tower, 1 mm gaps. The flywheel (Ø80–100, Ø8 bore, crank kit) and an 8 mm collar go outside one tower.",
   "Geometry: piston skirt flush with the ferrule face at bottom dead centre, so the lands never leave the bore; rod centres = wrist-pin height + crank height + stroke/2 (1.5 in: 58, 2 in: 70, 3 in: 95); rod angle under 11°. Stroke 16 / 24 / 36 mm = 0.46 × bore, which gives a 2 in alpha or beta ~42 mL swept per cylinder.",
   "Wrist pin: Ø3 rod cut to the length in the table (drill rod, music wire or a 3 mm dowel for 1.5 in); it is retained by the spool bore, no clips. Set the webs 180° apart on an alpha's second cylinder, or add the counterweighted cranks entry's webs for balance.",
   "LES: the piston the tri-clamp beta and alpha engines run in a stock spool with no liner."
  ],
  "table": {
   "columns": [
    "spool",
    "bore_mm",
    "piston_od_mm",
    "length_mm",
    "offset_mm",
    "wrist_pin_z_mm"
   ],
   "rows": [
    [
     "1.5",
     34.800000000000004,
     34.9,
     42,
     "+0.10",
     17.6
    ],
    [
     "1.5",
     34.800000000000004,
     34.7,
     42,
     "-0.10",
     17.6
    ],
    [
     "1.5",
     34.800000000000004,
     34.6,
     42,
     "-0.20",
     17.6
    ],
    [
     "1.5",
     34.800000000000004,
     34.5,
     42,
     "-0.30",
     17.6
    ],
    [
     "2",
     47.5,
     47.6,
     56,
     "+0.10",
     23.5
    ],
    [
     "2",
     47.5,
     47.4,
     56,
     "-0.10",
     23.5
    ],
    [
     "2",
     47.5,
     47.3,
     56,
     "-0.20",
     23.5
    ],
    [
     "2",
     47.5,
     47.2,
     56,
     "-0.30",
     23.5
    ],
    [
     "3",
     72.9,
     73,
     88,
     "+0.10",
     37
    ],
    [
     "3",
     72.9,
     72.8,
     88,
     "-0.10",
     37
    ],
    [
     "3",
     72.9,
     72.7,
     88,
     "-0.20",
     37
    ],
    [
     "3",
     72.9,
     72.6,
     88,
     "-0.30",
     37
    ]
   ]
  },
  "linkage": {
   "columns": [
    "spool",
    "stroke_mm",
    "crank_height_mm",
    "rod_centres_mm",
    "wrist_pin_z_mm",
    "tower_gap_mm",
    "bought"
   ],
   "rows": [
    [
     "1.5",
     16,
     32,
     58,
     17.6,
     21,
     "Ø8 × 80 shaft, 2 × 608, 2 × 623, Ø3 pin × 19, Ø3 wrist pin × 29"
    ],
    [
     "2",
     24,
     34,
     70,
     23.5,
     21,
     "Ø8 × 80 shaft, 2 × 608, 2 × 623, Ø3 pin × 19, Ø3 wrist pin × 42"
    ],
    [
     "3",
     36,
     40,
     95,
     37,
     21,
     "Ø8 × 80 shaft, 2 × 608, 2 × 623, Ø3 pin × 19, Ø3 wrist pin × 68"
    ]
   ]
  }
 },
 "sheet_text": "Tri-clamp power pistons and crank linkage: full-bore ring-less pistons, con-rods, crank webs and a clamp-on crank frame for 1.5, 2 and 3 in spools — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/tri-clamp-power-pistons/  (CC BY 4.0)\nBasis: 16 ga ASME BPE tube bores (1.5 in = 34.8 mm, 2 in = 47.5, 3 in = 72.9); finished ring-less piston fit 0.02–0.05 mm diametral (graphite-in-glass and lapped-aluminium Stirling practice); FDM print-and-lap offsets from the Xem Studio calibration coupons\nCatalog version: 2026-10-20\n\nSizes: see table below\n- A Stirling power piston has no ring and no O-ring: the seal is the fit. Finished diametral clearance 0.02–0.05 mm; the test is that the piston falls slowly through the spool under its own weight with the far end open and holds for several seconds with it closed.\n- You cannot print that fit. Print the closest offset your printer makes (f010/f020/f030 = 0.10/0.20/0.30 mm under bore after the hole/pin coupons have set your slicer), or the 'lap' version 0.10 mm over, then lap it in: 800 → 1500 grit wet, then metal polish, turning the piston in the actual spool on the lapping handle. PETG laps well; PLA galls. Finish with a dry graphite rub (pencil) and run it dry; oil adds friction and stiction in a Stirling.\n- Length 1.2 × bore keeps it from cocking: the two 8 mm lands at the ends carry the fit; the 0.4 mm relief between them halves the rubbing area and traps dust. Wrist pin Ø3 (dowel-pins-metric) at 0.42 L, con-rod small end with a 623 bearing from the crank kit; the skirt is open so the rod swings inside it.\n- Where it goes: beta engine (piston and displacer in one spool, displacer rod through the piston's wrist-pin gap), alpha (two spools at 90°, a piston in each, no displacer), or a big low-compression gamma (same-bore power cylinder: 1:1 swept ratio, suits an LTD on a hot plate). For a high-ratio gamma use the Ø20 piston from the power-cylinder entry instead.\n- The -rod variants (f020 and lap) have a Ø5 crown boss for a dry 3 × 5 × 6 bushing (graphite-bronze, PTFE, or sintered bronze degreased in acetone; no oil) so a Ø3 displacer rod runs through the piston on a clearance fit: that is the beta / rhombic / free-piston piston. The piston plug in the tri-clamp linkage kit drops into the skirt, is retained by the two wrist-pin dowels, and carries the 5 mm tube piston rod with the displacer rod inside it.\n- Mass: the 2 in piston prints at ~21 g in PETG (16.8 cm³); keep it light, it is the moving mass the flywheel has to swing.\n- Linkage, designed so nothing else is needed: the crank frame is an ISO 2852 cap with a con-rod window and two bearing towers, so a stock clamp holds it on the spool's open ferrule; a Ø8 shaft (shafts entry, 80–100 mm) runs in two 608s; two crank webs (Ø8 bore, M3 grub) carry a Ø3 pin at stroke/2 between them; the con-rod runs on 623s at both ends. Order along the shaft: tower · web · rod · web · tower, 1 mm gaps. The flywheel (Ø80–100, Ø8 bore, crank kit) and an 8 mm collar go outside one tower.\n- Geometry: piston skirt flush with the ferrule face at bottom dead centre, so the lands never leave the bore; rod centres = wrist-pin height + crank height + stroke/2 (1.5 in: 58, 2 in: 70, 3 in: 95); rod angle under 11°. Stroke 16 / 24 / 36 mm = 0.46 × bore, which gives a 2 in alpha or beta ~42 mL swept per cylinder.\n- Wrist pin: Ø3 rod cut to the length in the table (drill rod, music wire or a 3 mm dowel for 1.5 in); it is retained by the spool bore, no clips. Set the webs 180° apart on an alpha's second cylinder, or add the counterweighted cranks entry's webs for balance.\n- LES: the piston the tri-clamp beta and alpha engines run in a stock spool with no liner.\n\nspool  bore_mm  piston_od_mm  length_mm  offset_mm  wrist_pin_z_mm\n1.5  34.800000000000004  34.9  42  +0.10  17.6\n1.5  34.800000000000004  34.7  42  -0.10  17.6\n1.5  34.800000000000004  34.6  42  -0.20  17.6\n1.5  34.800000000000004  34.5  42  -0.30  17.6\n2  47.5  47.6  56  +0.10  23.5\n2  47.5  47.4  56  -0.10  23.5\n2  47.5  47.3  56  -0.20  23.5\n2  47.5  47.2  56  -0.30  23.5\n3  72.9  73.0  88  +0.10  37.0\n3  72.9  72.8  88  -0.10  37.0\n3  72.9  72.7  88  -0.20  37.0\n3  72.9  72.6  88  -0.30  37.0\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Long Earth Society: Tri-clamp Stirling engine builds — web, video — LES site — https://longearthsociety.com/engineering/\n- James R. Senft: An Introduction to Stirling Engines (piston fit and leakage) — book — Moriya Press [verify license at link] — https://www.stirlingengine.com/\n- ASME: BPE tube dimensions (16 ga sanitary tube) — standard — ASME [verify license at link] — https://www.asme.org/codes-standards/find-codes-standards/bpe-bioprocessing-equipment\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 30 parts): https://xemstudio.com/files/hardware/tri-clamp-power-pistons/index.json\nAPI: https://xemstudio.com/api/geometry?object=tri-clamp-power-pistons\n",
 "sources": [
  {
   "publisher": "Long Earth Society",
   "title": "Tri-clamp Stirling engine builds",
   "url": "https://longearthsociety.com/engineering/",
   "formats": [
    "web",
    "video"
   ],
   "license": "LES site",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "James R. Senft",
   "title": "An Introduction to Stirling Engines (piston fit and leakage)",
   "url": "https://www.stirlingengine.com/",
   "formats": [
    "book"
   ],
   "license": "Moriya Press",
   "license_verified": false,
   "hosted": false
  },
  {
   "publisher": "ASME",
   "title": "BPE tube dimensions (16 ga sanitary tube)",
   "url": "https://www.asme.org/codes-standards/find-codes-standards/bpe-bioprocessing-equipment",
   "formats": [
    "standard"
   ],
   "license": "ASME",
   "license_verified": false,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "tri-clamp-spool",
  "tri-clamp-cups",
  "tri-clamp-displacers-and-heads",
  "dowel-pins-metric",
  "shaft-collars-clips-and-shafts",
  "ball-bearings-metric",
  "crank-conrod-flywheel-kit",
  "counterweighted-cranks",
  "power-cylinder-piston-crosshead",
  "printer-calibration-coupons",
  "alpha-twin-crank-90"
 ],
 "fits": [
  {
   "role": "Goes in or on",
   "items": [
    {
     "slug": "tri-clamp-spool",
     "why": "runs in the 16 ga bore (34.8 / 47.5 / 72.9) with no ring"
    },
    {
     "slug": "tri-clamp-cups",
     "why": "same bore, closed end: the alpha or test cylinder"
    }
   ]
  },
  {
   "role": "Connects to",
   "items": [
    {
     "slug": "stirling-linkage-fittings",
     "why": "rod clevis on the 5 mm tube rod; rhombic frame head for a beta"
    },
    {
     "slug": "rhombic-drive-kit",
     "why": "the -rod piston's tube rod into the lower yoke"
    },
    {
     "slug": "tri-clamp-free-piston-kit",
     "why": "piston plug + tube rod onto the flexure stack"
    },
    {
     "slug": "crank-conrod-flywheel-kit",
     "why": "flywheel for the crank frame's Ø8 shaft"
    }
   ]
  },
  {
   "role": "Alternatives",
   "items": [
    {
     "slug": "power-cylinder-piston-crosshead",
     "why": "small Ø16–30 piston blanks and liners for a high-ratio gamma"
    },
    {
     "slug": "free-piston-core",
     "why": "Ø30 / Ø40 piston blanks in their own liner"
    },
    {
     "slug": "syringe-pistons",
     "why": "10–30 mL syringe barrels as the power cylinder"
    }
   ]
  },
  {
   "role": "Also needed",
   "items": [
    {
     "slug": "stirling-shafts-and-rods",
     "why": "Ø8 D-flat crankshaft for the crank frame, Ø3 pins, spacers"
    },
    {
     "slug": "nut-weighted-flywheels",
     "why": "Ø8-hub flywheel on the crank frame"
    },
    {
     "slug": "dowel-pins-metric",
     "why": "Ø3 × 16 wrist pins"
    },
    {
     "slug": "ball-bearings-metric",
     "why": "608 for the crank frame, 623 in the con-rod"
    },
    {
     "slug": "shaft-collars-clips-and-shafts",
     "why": "Ø8 crankshaft, collars"
    },
    {
     "slug": "bearing-housings-and-rod-supports",
     "why": "3 × 5 × 6 bushing in the -rod piston's crown"
    },
    {
     "slug": "tri-clamp-clamps",
     "why": "clamps the crank frame to the spool"
    },
    {
     "slug": "printer-calibration-coupons",
     "why": "set the slicer before printing a fit"
    }
   ]
  }
 ],
 "faq": [
  {
   "q": "How much clearance does a Stirling piston need without rings?",
   "a": "0.02–0.05 mm on diameter when finished. It should sink slowly through the open spool under its own weight and hold for seconds with the end closed."
  },
  {
   "q": "Which piston file do I print for a 2 inch spool?",
   "a": "Start with piston-2in-f020 (Ø47.30 for the 47.5 bore). If it drops straight through, print f010; if it will not enter, f030. Then lap to the final fit in the spool itself."
  },
  {
   "q": "How do I lap a printed piston?",
   "a": "Plug the lapping handle into the open skirt, wet 800 grit wrapped on the piston, turn and stroke it in the real spool, step to 1500 and polish, wash, rub pencil graphite in and run it dry."
  },
  {
   "q": "Why not an O-ring?",
   "a": "An O-ring's friction eats most of a model Stirling's few hundred milliwatts; the piston would stall. The fit is the seal, as in graphite-and-glass engines."
  },
  {
   "q": "How do I connect the piston to a crankshaft?",
   "a": "Print the crank frame for your spool size, two crank webs and the con-rod; clamp the frame to the spool's open ferrule with a stock clamp, press two 608s into the towers, run a Ø8 shaft through, set the webs with the Ø3 pin between them and the con-rod on it, and the other end of the rod on the Ø3 wrist pin in the piston. Flywheel outside one tower."
  },
  {
   "q": "Why two lands with a relief between?",
   "a": "Only the ends touch the bore, so friction halves while the full length still keeps the piston aligned; dust collects in the relief instead of scoring the bore."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "piston-1.5in-lap",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-1.5in-lap.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-1.5in-lap.stl",
   "note": "1.5 in full-bore piston Ø34.90 × 42 (lapping stock, +0.10 over bore), two 8 mm lands, Ø3 wrist pin at 17.6 mm, open skirt; print crown up, 0.1 mm layers"
  },
  {
   "file": "piston-1.5in-lap-rod",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-1.5in-lap-rod.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-1.5in-lap-rod.stl",
   "note": "1.5 in piston as above with a Ø5.0 centre bore and boss in the crown for a dry 3 × 5 × 6 bushing (no oil): the displacer rod passes through it (beta, rhombic, free-piston)"
  },
  {
   "file": "piston-1.5in-f010",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-1.5in-f010.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-1.5in-f010.stl",
   "note": "1.5 in full-bore piston Ø34.70 × 42 (0.10 mm under bore), two 8 mm lands, Ø3 wrist pin at 17.6 mm, open skirt; print crown up, 0.1 mm layers"
  },
  {
   "file": "piston-1.5in-f020",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-1.5in-f020.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-1.5in-f020.stl",
   "note": "1.5 in full-bore piston Ø34.60 × 42 (0.20 mm under bore), two 8 mm lands, Ø3 wrist pin at 17.6 mm, open skirt; print crown up, 0.1 mm layers"
  },
  {
   "file": "piston-1.5in-f020-rod",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-1.5in-f020-rod.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-1.5in-f020-rod.stl",
   "note": "1.5 in piston as above with a Ø5.0 centre bore and boss in the crown for a dry 3 × 5 × 6 bushing (no oil): the displacer rod passes through it (beta, rhombic, free-piston)"
  },
  {
   "file": "piston-1.5in-f030",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-1.5in-f030.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-1.5in-f030.stl",
   "note": "1.5 in full-bore piston Ø34.50 × 42 (0.30 mm under bore), two 8 mm lands, Ø3 wrist pin at 17.6 mm, open skirt; print crown up, 0.1 mm layers"
  },
  {
   "file": "lapping-handle-1.5in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/lapping-handle-1.5in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/lapping-handle-1.5in.stl",
   "note": "1.5 in lapping handle: plug into the open skirt and a T-bar to turn the piston in the spool with lapping compound"
  },
  {
   "file": "crank-frame-1.5in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/crank-frame-1.5in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/crank-frame-1.5in.stl",
   "note": "1.5 in crank frame: ISO 2852 cap face (clamps to the spool with a stock clamp), Ø21 con-rod window, two towers with 608 pockets for a Ø8 crankshaft 32 mm above the face, 21 mm between towers"
  },
  {
   "file": "crank-web-1.5in-s16",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/crank-web-1.5in-s16.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/crank-web-1.5in-s16.stl",
   "note": "1.5 in crank web: Ø8 bore with M3 grub, Ø3 pin at 8 mm (16 mm stroke); print two"
  },
  {
   "file": "conrod-1.5in-58",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/conrod-1.5in-58.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/conrod-1.5in-58.stl",
   "note": "1.5 in con-rod, 58 mm centres, 5 mm thick, 623 pockets both ends (wrist pin and crank pin Ø3)"
  },
  {
   "file": "piston-2in-lap",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-2in-lap.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-2in-lap.stl",
   "note": "2 in full-bore piston Ø47.60 × 56 (lapping stock, +0.10 over bore), two 8 mm lands, Ø3 wrist pin at 23.5 mm, open skirt; print crown up, 0.1 mm layers"
  },
  {
   "file": "piston-2in-lap-rod",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-2in-lap-rod.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-2in-lap-rod.stl",
   "note": "2 in piston as above with a Ø5.0 centre bore and boss in the crown for a dry 3 × 5 × 6 bushing (no oil): the displacer rod passes through it (beta, rhombic, free-piston)"
  },
  {
   "file": "piston-2in-f010",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-2in-f010.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-2in-f010.stl",
   "note": "2 in full-bore piston Ø47.40 × 56 (0.10 mm under bore), two 8 mm lands, Ø3 wrist pin at 23.5 mm, open skirt; print crown up, 0.1 mm layers"
  },
  {
   "file": "piston-2in-f020",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-2in-f020.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-2in-f020.stl",
   "note": "2 in full-bore piston Ø47.30 × 56 (0.20 mm under bore), two 8 mm lands, Ø3 wrist pin at 23.5 mm, open skirt; print crown up, 0.1 mm layers"
  },
  {
   "file": "piston-2in-f020-rod",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-2in-f020-rod.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-2in-f020-rod.stl",
   "note": "2 in piston as above with a Ø5.0 centre bore and boss in the crown for a dry 3 × 5 × 6 bushing (no oil): the displacer rod passes through it (beta, rhombic, free-piston)"
  },
  {
   "file": "piston-2in-f030",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-2in-f030.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-2in-f030.stl",
   "note": "2 in full-bore piston Ø47.20 × 56 (0.30 mm under bore), two 8 mm lands, Ø3 wrist pin at 23.5 mm, open skirt; print crown up, 0.1 mm layers"
  },
  {
   "file": "lapping-handle-2in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/lapping-handle-2in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/lapping-handle-2in.stl",
   "note": "2 in lapping handle: plug into the open skirt and a T-bar to turn the piston in the spool with lapping compound"
  },
  {
   "file": "crank-frame-2in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/crank-frame-2in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/crank-frame-2in.stl",
   "note": "2 in crank frame: ISO 2852 cap face (clamps to the spool with a stock clamp), Ø28 con-rod window, two towers with 608 pockets for a Ø8 crankshaft 34 mm above the face, 21 mm between towers"
  },
  {
   "file": "crank-web-2in-s24",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/crank-web-2in-s24.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/crank-web-2in-s24.stl",
   "note": "2 in crank web: Ø8 bore with M3 grub, Ø3 pin at 12 mm (24 mm stroke); print two"
  },
  {
   "file": "conrod-2in-70",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/conrod-2in-70.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/conrod-2in-70.stl",
   "note": "2 in con-rod, 70 mm centres, 5 mm thick, 623 pockets both ends (wrist pin and crank pin Ø3)"
  },
  {
   "file": "piston-3in-lap",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-3in-lap.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-3in-lap.stl",
   "note": "3 in full-bore piston Ø73.00 × 88 (lapping stock, +0.10 over bore), two 8 mm lands, Ø3 wrist pin at 37.0 mm, open skirt; print crown up, 0.1 mm layers"
  },
  {
   "file": "piston-3in-lap-rod",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-3in-lap-rod.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-3in-lap-rod.stl",
   "note": "3 in piston as above with a Ø5.0 centre bore and boss in the crown for a dry 3 × 5 × 6 bushing (no oil): the displacer rod passes through it (beta, rhombic, free-piston)"
  },
  {
   "file": "piston-3in-f010",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-3in-f010.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-3in-f010.stl",
   "note": "3 in full-bore piston Ø72.80 × 88 (0.10 mm under bore), two 8 mm lands, Ø3 wrist pin at 37.0 mm, open skirt; print crown up, 0.1 mm layers"
  },
  {
   "file": "piston-3in-f020",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-3in-f020.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-3in-f020.stl",
   "note": "3 in full-bore piston Ø72.70 × 88 (0.20 mm under bore), two 8 mm lands, Ø3 wrist pin at 37.0 mm, open skirt; print crown up, 0.1 mm layers"
  },
  {
   "file": "piston-3in-f020-rod",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-3in-f020-rod.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-3in-f020-rod.stl",
   "note": "3 in piston as above with a Ø5.0 centre bore and boss in the crown for a dry 3 × 5 × 6 bushing (no oil): the displacer rod passes through it (beta, rhombic, free-piston)"
  },
  {
   "file": "piston-3in-f030",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-3in-f030.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/piston-3in-f030.stl",
   "note": "3 in full-bore piston Ø72.60 × 88 (0.30 mm under bore), two 8 mm lands, Ø3 wrist pin at 37.0 mm, open skirt; print crown up, 0.1 mm layers"
  },
  {
   "file": "lapping-handle-3in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/lapping-handle-3in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/lapping-handle-3in.stl",
   "note": "3 in lapping handle: plug into the open skirt and a T-bar to turn the piston in the spool with lapping compound"
  },
  {
   "file": "crank-frame-3in",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/crank-frame-3in.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/crank-frame-3in.stl",
   "note": "3 in crank frame: ISO 2852 cap face (clamps to the spool with a stock clamp), Ø44 con-rod window, two towers with 608 pockets for a Ø8 crankshaft 40 mm above the face, 21 mm between towers"
  },
  {
   "file": "crank-web-3in-s36",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/crank-web-3in-s36.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/crank-web-3in-s36.stl",
   "note": "3 in crank web: Ø8 bore with M3 grub, Ø3 pin at 18 mm (36 mm stroke); print two"
  },
  {
   "file": "conrod-3in-95",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/conrod-3in-95.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-power-pistons/conrod-3in-95.stl",
   "note": "3 in con-rod, 95 mm centres, 5 mm thick, 623 pockets both ends (wrist pin and crank pin Ø3)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/tri-clamp-power-pistons/index.md"
}