{
 "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": "linear-alternator-module-open-frame-2in",
 "name": "Linear alternator module open frame, 2 in: frame base, leaf seats, clamp rings, stator sleeve and top plate",
 "kind": "hardware",
 "category": "Electronics",
 "group": "Generators & alternators",
 "year": null,
 "question": "What frame carries the leaves and stator of the open-frame linear alternator module?",
 "tags": [
  "frame",
  "open frame",
  "flexure",
  "linear alternator",
  "leaf spring",
  "stator",
  "tri-clamp",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "linear alternator open frame",
  "flexure frame tri clamp",
  "open frame linear alternator",
  "leaf spring seat ring",
  "stator sleeve linear alternator"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 6,
 "url": "https://xemstudio.com/objects/linear-alternator-module-open-frame-2in/",
 "sheet_txt": "https://xemstudio.com/objects/linear-alternator-module-open-frame-2in/sheet.txt",
 "sheet": {
  "basis": "Design values, my geometry (tools/gen_la_module.py); the frame base's clamp face is the 2 in ISO 2852 end-cap profile drawn in tools/gen_hardware.py",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Six parts that make the open frame of my linear alternator module. The frame base clamps on the 42 mm bored spool's second ferrule with a Type B gasket and a standard 2 in clamp, exactly as an end cap; everything else stacks on it with M3 screws, nothing around the sides: leaf 1 · lower clamp ring and its three posts · stator sleeve with the stator · top plate and its three posts · leaf-2 seat ring · leaf 2 · upper clamp ring.",
   "Each leaf's Ø64 rim sits in a Ø64 × 0.8 seat (the 0.8 leaf's thickness) and a flat Ø80 clamp ring presses it down, screws on r 36 outside the leaf, so no hole goes through a leaf. The rim is clamped inside r 23.75 = 47.5 / 2 exactly as in a spool joint, so the leaves' free span, stiffness and stress are the same as in the closed module. A 0.5 soft leaf sits on a 0.3 rim shim (tuning page).",
   "The stator sleeve keeps the alternator's magnetic gap: its Ø50.8 outside is where the stator teeth sit (as on the bored spool) and its Ø48.00 bore leaves the same 0.5 radial gap to the Ø47 magnet carrier, so the force constant, coil and side pull are the closed module's. The bobbin goes on over the Ø64 top flange before the packs; the lower Ø80 flange carries the sleeve on the lower posts.",
   "Screws: 3 × M3 × 25 down through the sleeve's lower flange, the 10 mm posts and the lower clamp ring into the frame base (7 engaged in its 7.5 mm tapped holes); 3 × M3 × 12 through the top plate into the sleeve's top flange; 3 × M3 × 16 through the upper clamp ring and the seat ring into the top plate's posts. Every tapped hole is drawn at the Ø2.5 M3 tap drill.",
   "The back of the piston is at the room's pressure: it breathes through the frame base's Ø47.5 bore, past leaf 1 and out of the 10 mm side opening between the lower clamp ring and the sleeve (1492 mm² at the bore circle against the piston's 1810 mm²).",
   "Every frame part is a flat ring or a round body with flat faces at both ends and no undercut; the slopes behind the base's neck and under the sleeve's top flange are 45°. Fits are in the table; everything else is drawn at size."
  ],
  "table": {
   "columns": [
    "part",
    "what it is",
    "size_mm",
    "fits",
    "qty"
   ],
   "rows": [
    [
     "la-frame-base-2in-ferrule",
     "frame base (ferrule face, leaf-1 seat)",
     "Ø80 × 28",
     "ISO 2852 face: clamp; seat Ø64 × 0.8: clamp (leaf rim); bore Ø47.5: designed",
     1
    ],
    [
     "la-frame-leaf-clamp-ring-80-posts10",
     "lower leaf clamp ring with posts",
     "Ø80 × 13",
     "face on the leaf rim: clamp",
     1
    ],
    [
     "la-frame-stator-sleeve-48x66",
     "stator sleeve",
     "Ø80 × 66, bore Ø48.00",
     "OD Ø50.8: clamp (stator teeth); bore Ø48.00: designed (0.5 radial gap to the Ø47 carrier)",
     1
    ],
    [
     "la-frame-stator-top-plate-80-posts5",
     "stator top plate with posts",
     "Ø80 × 10",
     "faces: flat bolted joints",
     1
    ],
    [
     "la-frame-leaf-seat-ring-80",
     "leaf-2 seat ring",
     "Ø80 × 4",
     "seat Ø64 × 0.8: clamp (leaf rim)",
     1
    ],
    [
     "la-frame-leaf-clamp-ring-80",
     "upper leaf clamp ring",
     "Ø80 × 3",
     "face on the leaf rim: clamp",
     1
    ]
   ]
  }
 },
 "sheet_text": "Linear alternator module open frame, 2 in: frame base, leaf seats, clamp rings, stator sleeve and top plate — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/linear-alternator-module-open-frame-2in/  (CC BY 4.0)\nBasis: Design values, my geometry (tools/gen_la_module.py); the frame base's clamp face is the 2 in ISO 2852 end-cap profile drawn in tools/gen_hardware.py\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Six parts that make the open frame of my linear alternator module. The frame base clamps on the 42 mm bored spool's second ferrule with a Type B gasket and a standard 2 in clamp, exactly as an end cap; everything else stacks on it with M3 screws, nothing around the sides: leaf 1 · lower clamp ring and its three posts · stator sleeve with the stator · top plate and its three posts · leaf-2 seat ring · leaf 2 · upper clamp ring.\n- Each leaf's Ø64 rim sits in a Ø64 × 0.8 seat (the 0.8 leaf's thickness) and a flat Ø80 clamp ring presses it down, screws on r 36 outside the leaf, so no hole goes through a leaf. The rim is clamped inside r 23.75 = 47.5 / 2 exactly as in a spool joint, so the leaves' free span, stiffness and stress are the same as in the closed module. A 0.5 soft leaf sits on a 0.3 rim shim (tuning page).\n- The stator sleeve keeps the alternator's magnetic gap: its Ø50.8 outside is where the stator teeth sit (as on the bored spool) and its Ø48.00 bore leaves the same 0.5 radial gap to the Ø47 magnet carrier, so the force constant, coil and side pull are the closed module's. The bobbin goes on over the Ø64 top flange before the packs; the lower Ø80 flange carries the sleeve on the lower posts.\n- Screws: 3 × M3 × 25 down through the sleeve's lower flange, the 10 mm posts and the lower clamp ring into the frame base (7 engaged in its 7.5 mm tapped holes); 3 × M3 × 12 through the top plate into the sleeve's top flange; 3 × M3 × 16 through the upper clamp ring and the seat ring into the top plate's posts. Every tapped hole is drawn at the Ø2.5 M3 tap drill.\n- The back of the piston is at the room's pressure: it breathes through the frame base's Ø47.5 bore, past leaf 1 and out of the 10 mm side opening between the lower clamp ring and the sleeve (1492 mm² at the bore circle against the piston's 1810 mm²).\n- Every frame part is a flat ring or a round body with flat faces at both ends and no undercut; the slopes behind the base's neck and under the sleeve's top flange are 45°. Fits are in the table; everything else is drawn at size.\n\npart  what it is  size_mm  fits  qty\nla-frame-base-2in-ferrule  frame base (ferrule face, leaf-1 seat)  Ø80 × 28  ISO 2852 face: clamp; seat Ø64 × 0.8: clamp (leaf rim); bore Ø47.5: designed  1\nla-frame-leaf-clamp-ring-80-posts10  lower leaf clamp ring with posts  Ø80 × 13  face on the leaf rim: clamp  1\nla-frame-stator-sleeve-48x66  stator sleeve  Ø80 × 66, bore Ø48.00  OD Ø50.8: clamp (stator teeth); bore Ø48.00: designed (0.5 radial gap to the Ø47 carrier)  1\nla-frame-stator-top-plate-80-posts5  stator top plate with posts  Ø80 × 10  faces: flat bolted joints  1\nla-frame-leaf-seat-ring-80  leaf-2 seat ring  Ø80 × 4  seat Ø64 × 0.8: clamp (leaf rim)  1\nla-frame-leaf-clamp-ring-80  upper leaf clamp ring  Ø80 × 3  face on the leaf rim: clamp  1\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Xem Studio: tools/gen_la_module.py: the module's geometry, masses, bounce volume, natural frequencies and every number on these pages — code — CC BY 4.0 — https://xemstudio.com/\n- Xem Studio: tools/gen_fpse_gen.py: the free-piston generator whose stator, magnets, leaves and collars this module reuses; its leaf frame model and magnetic-circuit estimate — code — CC BY 4.0 — https://xemstudio.com/\n- ISO (via iTeh sample): ISO 2852 clamp liners: face profile and flange / groove diameters — PDF — standard excerpt; dimensions are facts — https://cdn.standards.iteh.ai/samples/7850/eb49c396488d408c8ced3e2961d76cf3/ISO-2852-1974.pdf\n- ASME: BPE Bioprocessing Equipment (tube OD and wall, clamp fittings) — standard — ASME; dimensions are facts [verify license at link] — https://www.asme.org/codes-standards/find-codes-standards/bpe-bioprocessing-equipment\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, 6 parts): https://xemstudio.com/files/hardware/linear-alternator-module-open-frame-2in/index.json\nAPI: https://xemstudio.com/api/geometry?object=linear-alternator-module-open-frame-2in\n",
 "sources": [
  {
   "publisher": "Xem Studio",
   "title": "tools/gen_la_module.py: the module's geometry, masses, bounce volume, natural frequencies and every number on these pages",
   "url": "https://xemstudio.com/",
   "formats": [
    "code"
   ],
   "license": "CC BY 4.0",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Xem Studio",
   "title": "tools/gen_fpse_gen.py: the free-piston generator whose stator, magnets, leaves and collars this module reuses; its leaf frame model and magnetic-circuit estimate",
   "url": "https://xemstudio.com/",
   "formats": [
    "code"
   ],
   "license": "CC BY 4.0",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "ISO (via iTeh sample)",
   "title": "ISO 2852 clamp liners: face profile and flange / groove diameters",
   "url": "https://cdn.standards.iteh.ai/samples/7850/eb49c396488d408c8ced3e2961d76cf3/ISO-2852-1974.pdf",
   "formats": [
    "PDF"
   ],
   "license": "standard excerpt; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "ASME",
   "title": "BPE Bioprocessing Equipment (tube OD and wall, clamp fittings)",
   "url": "https://www.asme.org/codes-standards/find-codes-standards/bpe-bioprocessing-equipment",
   "formats": [
    "standard"
   ],
   "license": "ASME; dimensions are facts",
   "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": [
  "linear-alternator-module-spools-2in",
  "linear-alternator-module-mover-2in",
  "linear-alternator-module-tuning-2in",
  "fpse-linear-alternator-stator",
  "tri-clamp-flexure-leaf",
  "tri-clamp-flexure-head",
  "linear-alternator-module-2in-datasheet",
  "list-linear-alternator-module-2in-open"
 ],
 "fits": [],
 "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": "face",
   "exact": "ISO 2852 2 in end-cap face (recess Ø56.5 × 1.6, 20° back cone)",
   "mates": "Type B gasket + standard 2 in clamp on the 42 mm bored spool's second ferrule",
   "fit": "clamp",
   "files": "la-frame-base"
  },
  {
   "feature": "neck",
   "exact": "Ø50.8 to 9.5 from the face",
   "mates": "clamp groove room (no contact)",
   "fit": "designed",
   "files": "la-frame-base"
  },
  {
   "feature": "leaf seat",
   "exact": "annulus Ø47.5–Ø64 × 0.8",
   "mates": "leaf 1's Ø64 rim (0.8 leaf, or 0.5 leaf on a 0.3 shim), clamped by the lower clamp ring",
   "fit": "clamp",
   "files": "la-frame-base"
  },
  {
   "feature": "bore",
   "exact": "Ø47.5 through",
   "mates": "collar Ø28 and tube rod pass (no contact); the piston back breathes through it",
   "fit": "designed",
   "files": "la-frame-base"
  },
  {
   "feature": "tapped holes",
   "exact": "3 × Ø2.5 × 7.5 on r 36",
   "mates": "M3 × 25 frame screws (M3 tap drill)",
   "fit": "designed",
   "files": "la-frame-base"
  },
  {
   "feature": "clamp face",
   "exact": "Ø47.5–Ø80 flat",
   "mates": "leaf rim (inside Ø64) and the seat's top face",
   "fit": "clamp",
   "files": "la-frame-leaf-clamp-ring"
  },
  {
   "feature": "holes",
   "exact": "3 × Ø3.4 on r 36 (through the posts)",
   "mates": "M3 clearance (ISO 273 medium)",
   "fit": "designed",
   "files": "la-frame-leaf-clamp-ring"
  },
  {
   "feature": "post ends",
   "exact": "3 × Ø8 × 10 on r 36",
   "mates": "stator sleeve's lower flange",
   "fit": "clamp",
   "files": "la-frame-leaf-clamp-ring-80-posts"
  },
  {
   "feature": "OD",
   "exact": "Ø50.8 from s −28 to s 20",
   "mates": "stator pack teeth (r 25.4) and the housing halves",
   "fit": "clamp",
   "files": "la-frame-stator-sleeve"
  },
  {
   "feature": "bore",
   "exact": "Ø48.00 × 66",
   "mates": "magnet carrier Ø47 (0.5 radial gap, no contact)",
   "fit": "designed",
   "files": "la-frame-stator-sleeve"
  },
  {
   "feature": "top flange",
   "exact": "Ø64",
   "mates": "bobbin bore Ø65 passes over (no contact)",
   "fit": "designed",
   "files": "la-frame-stator-sleeve"
  },
  {
   "feature": "lower flange",
   "exact": "Ø80 × 5, 3 × Ø3.4 on r 36",
   "mates": "lower posts; M3 × 25",
   "fit": "clamp",
   "files": "la-frame-stator-sleeve"
  },
  {
   "feature": "tapped holes",
   "exact": "3 × Ø2.5 × 8 on r 28.5",
   "mates": "M3 × 12 from the top plate (M3 tap drill)",
   "fit": "designed",
   "files": "la-frame-stator-sleeve"
  },
  {
   "feature": "underside",
   "exact": "Ø48–Ø80 flat, 3 × Ø3.4 on r 28.5",
   "mates": "sleeve's top flange; M3 × 12",
   "fit": "clamp",
   "files": "la-frame-stator-top-plate"
  },
  {
   "feature": "posts",
   "exact": "3 × Ø8 × 5 on r 36, Ø2.5 tapped through post and plate",
   "mates": "seat ring underside; M3 × 16 (M3 tap drill)",
   "fit": "clamp",
   "files": "la-frame-stator-top-plate"
  },
  {
   "feature": "leaf seat",
   "exact": "annulus Ø47.5–Ø64 × 0.8",
   "mates": "leaf 2's Ø64 rim, clamped by the upper clamp ring",
   "fit": "clamp",
   "files": "la-frame-leaf-seat-ring"
  },
  {
   "feature": "holes",
   "exact": "3 × Ø3.4 on r 36",
   "mates": "M3 clearance (ISO 273 medium)",
   "fit": "designed",
   "files": "la-frame-leaf-seat-ring"
  }
 ],
 "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 an open frame?",
   "a": "Nothing hides the leaves: you can watch them flex, swap a leaf or a mass disc without opening a joint, and check the mover by hand. The back of the piston is simply at the room's pressure, which is what an unpressurised engine wants."
  },
  {
   "q": "Can the leaves go into a spool joint instead?",
   "a": "Yes: the same leaves (Ø64 rim) clamp between two half gaskets in any 2 in spool-to-spool joint, as in the closed module. The frame's seats are drawn to the same rim and the same clamped radius, so a leaf behaves the same in either mount."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "la-frame-base-2in-ferrule",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/linear-alternator-module-open-frame-2in/la-frame-base-2in-ferrule.step",
   "stl": "https://xemstudio.com/files/hardware/linear-alternator-module-open-frame-2in/la-frame-base-2in-ferrule.stl",
   "note": "frame base: 2 in ISO 2852 end-cap face (clamps on the 42 mm spool's ferrule with a Type B gasket and a standard clamp), Ø50.8 neck to 9.5, 45° cone to Ø80, flat top at 28 with the leaf-1 rim seat (annulus Ø47.5–Ø64 × 0.8), bore Ø47.5 through, 3 × M3 tapped (Ø2.5 × 7.5) on r 36"
  },
  {
   "file": "la-frame-leaf-clamp-ring-80-posts10",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/linear-alternator-module-open-frame-2in/la-frame-leaf-clamp-ring-80-posts10.step",
   "stl": "https://xemstudio.com/files/hardware/linear-alternator-module-open-frame-2in/la-frame-leaf-clamp-ring-80-posts10.stl",
   "note": "lower leaf clamp ring with posts: Ø80 / Ø47.5 × 3 on leaf 1's rim, three Ø8 × 10 posts on r 36 carrying the stator sleeve, Ø3.4 through each post"
  },
  {
   "file": "la-frame-stator-sleeve-48x66",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/linear-alternator-module-open-frame-2in/la-frame-stator-sleeve-48x66.step",
   "stl": "https://xemstudio.com/files/hardware/linear-alternator-module-open-frame-2in/la-frame-stator-sleeve-48x66.stl",
   "note": "stator sleeve: bore Ø48.00 × 66 (the magnet carrier's running gap), Ø50.8 outside under the stator teeth, lower flange Ø80 × 5 with 3 × Ø3.4 on r 36, 45° cone to the Ø64 top flange (the bobbin's Ø65 bore passes over it), 3 × M3 tapped (Ø2.5 × 8) in the top on r 28.5"
  },
  {
   "file": "la-frame-stator-top-plate-80-posts5",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/linear-alternator-module-open-frame-2in/la-frame-stator-top-plate-80-posts5.step",
   "stl": "https://xemstudio.com/files/hardware/linear-alternator-module-open-frame-2in/la-frame-stator-top-plate-80-posts5.stl",
   "note": "stator top plate with posts: Ø80 / Ø48 × 5, 3 × Ø3.4 on r 28.5 to the sleeve, three Ø8 × 5 posts on r 36, M3 tapped (Ø2.5) through post and plate"
  },
  {
   "file": "la-frame-leaf-seat-ring-80",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/linear-alternator-module-open-frame-2in/la-frame-leaf-seat-ring-80.step",
   "stl": "https://xemstudio.com/files/hardware/linear-alternator-module-open-frame-2in/la-frame-leaf-seat-ring-80.stl",
   "note": "leaf-2 seat ring: Ø80 / Ø47.5 × 4, rim seat annulus Ø47.5–Ø64 × 0.8 in the top face, 3 × Ø3.4 on r 36"
  },
  {
   "file": "la-frame-leaf-clamp-ring-80",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/linear-alternator-module-open-frame-2in/la-frame-leaf-clamp-ring-80.step",
   "stl": "https://xemstudio.com/files/hardware/linear-alternator-module-open-frame-2in/la-frame-leaf-clamp-ring-80.stl",
   "note": "upper leaf clamp ring: Ø80 / Ø47.5 × 3 on leaf 2's rim, 3 × Ø3.4 on r 36"
  }
 ],
 "markdown": "https://xemstudio.com/objects/linear-alternator-module-open-frame-2in/index.md"
}