{
 "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": "list-tri-clamp-sealed-diaphragm-generator",
 "name": "Build list: Tri-clamp sealed diaphragm generator, 2 in",
 "kind": "list",
 "category": "Stirling engines",
 "group": "Guide",
 "year": null,
 "question": "What parts do I need to build a Tri-clamp sealed diaphragm generator, 2 in?",
 "tags": [
  "list",
  "build",
  "stirling",
  "long earth society",
  "tri-clamp",
  "diaphragm",
  "gamma",
  "sealed",
  "generator",
  "torch"
 ],
 "aliases": [
  "sealed stirling generator",
  "pressurised stirling tri clamp",
  "diaphragm stirling generator",
  "stirling engine generator no shaft seal",
  "torch stirling generator",
  "tri clamp stirling build list"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "not-scanned",
 "les": true,
 "free_files": 0,
 "url": "https://xemstudio.com/objects/list-tri-clamp-sealed-diaphragm-generator/",
 "sheet_txt": "https://xemstudio.com/objects/list-tri-clamp-sealed-diaphragm-generator/sheet.txt",
 "sheet": {
  "basis": "Every part is a free STEP/STL on this site or a standard part with its own page; quantities are the full count, every screw, nut, pin, gasket and clamp.",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "A sealed, pressurised gamma Stirling generator in 2 in tri-clamp: a plain closed-end cup over a torch, a power membrane between the working space and a sealed cross, and a 2208 gimbal motor geared to the crank inside the cross, its leads out through a sealed pass-through.",
   "Numbers: Membrane 2 in at 12 mm: 11.33 mL swept · displacer Ø46 × 120 at 12 mm: 21.3 mL · dead volume 52.0 mL · swept / dead 0.218 · charge 2 bar gauge · Schmidt (600–700 K / 320 K): ±0.49–0.55 bar, 0.57–0.69 J per cycle · at 900 rpm about 4–8 W at the crank (West / Beale); 2208 gimbal generator at 2520 rpm, 19.7 V open circuit, about 2.1–5.5 W at 14–18 V out of 4–8 W at the crank"
  ],
  "table": {
   "columns": [
    "subsystem",
    "object",
    "parts",
    "qty",
    "note"
   ],
   "rows": [
    [
     null,
     "tri-clamp-sealed-generator-frame",
     "sealed-generator-frame-2in",
     1,
     "base, wall, gussets"
    ],
    [
     null,
     "tri-clamp-torch-stand",
     "torch-stand-40",
     1,
     "on the base under the hot head, post toward +Y"
    ],
    [
     null,
     "socket-head-cap-screws-metric",
     "shcs-m4x10",
     5,
     "torch stand (2) and shroud feet (3) to the base"
    ],
    [
     null,
     "set-screws-metric",
     "set-m4x10",
     3,
     "centre the torch head in the stand ring"
    ],
    [
     null,
     "tri-clamp-burner-shroud",
     "burner-shroud-2in",
     1,
     "round the hot end, on its three feet"
    ],
    [
     null,
     "tri-clamp-cups",
     "cup-2in-150",
     1,
     "the hot end: a plain closed-end 2 in × 150 spool, face up; the displacer inside"
    ],
    [
     null,
     "tri-clamp-hot-fin-sleeve",
     "hot-fin-sleeve-2in-80x9",
     1,
     "optional heat exchanger: slides over the cup's closed end inside the shroud; without it the engine runs with less power"
    ],
    [
     null,
     "set-screws-metric",
     "set-m4x4",
     3,
     "optional: hold the fin sleeve (only with the sleeve)"
    ],
    [
     null,
     "tri-clamp-jacket-shell",
     "jacket-half-2in-56",
     2,
     "optional heat exchanger: round the cup under the clamp, the fill is the builder's choice; or cool the cold end any other way"
    ],
    [
     null,
     "tri-clamp-jacket-shell",
     "jacket-port-cap",
     2,
     "optional: one per jacket half (only with the jacket)"
    ],
    [
     null,
     "socket-head-cap-screws-metric",
     "shcs-m4x30",
     4,
     "optional: jacket ears (only with the jacket)"
    ],
    [
     null,
     "hex-nuts-metric",
     "nut-m4",
     4,
     "optional: jacket ears (only with the jacket)"
    ],
    [
     null,
     "hex-nuts-metric",
     "nut-m4",
     2,
     "hanger ears"
    ],
    [
     null,
     "tri-clamp-displacer",
     "displacer-shell-2in-120",
     1,
     "Ø46 × 120, 0.75 radial gap, 12 stroke"
    ],
    [
     null,
     "tri-clamp-displacer",
     "displacer-cap-2in",
     1,
     "closes the shell, holds the rod"
    ],
    [
     null,
     "stirling-crankshafts",
     "crankshaft-3x60",
     1,
     "displacer rod (Ø3 × 60), through the membrane and the crosshead's guide"
    ],
    [
     null,
     "tri-clamp-through-rod-membrane",
     "membrane-2in-hole5",
     1,
     "clamped between the hot cup and the cross, in place of a gasket"
    ],
    [
     null,
     "tri-clamp-diaphragm-crosshead",
     "crosshead-2in-p29.25",
     1,
     "crankcase side of the membrane: Ø3 guide (the bleed), con-rod pin on its arm"
    ],
    [
     null,
     "tri-clamp-diaphragm-crosshead",
     "backing-2in-m2-tapped",
     1,
     "working side of the membrane, M2 tapped"
    ],
    [
     null,
     "socket-head-cap-screws-metric",
     "shcs-m2x6",
     3,
     "heads on the crosshead, into the backing disc"
    ],
    [
     null,
     "sanitary-clamp-crosses",
     "cross-2in",
     1,
     "the crankcase: run vertical, branches along the crankshaft"
    ],
    [
     null,
     "tri-clamp-motor-mount-plate",
     "motor-mount-plate-2in-2208",
     1,
     "on the top of the cross; the motor hangs from it"
    ],
    [
     null,
     "tri-clamp-port-cap",
     "port-cap-2in-4x-npt18",
     1,
     "on the motor-mount plate"
    ],
    [
     null,
     "npt-thread-envelopes",
     "npt-1-8-male",
     4,
     "the 1/8 NPT stems of the fill valve, the pressure gauge, the relief valve and the sealed electrical pass-through (the bodies are the builder's choice)"
    ],
    [
     null,
     "tri-clamp-end-cap",
     "tc-cap-2in-flat",
     2,
     "close the two bearing plates"
    ],
    [
     null,
     "tri-clamp-gasket",
     "tc-gasket-2in",
     6,
     "cross–mount plate, mount plate–port cap, two cross–bearing plate, two bearing plate–end cap"
    ],
    [
     null,
     "tri-clamp-clamps",
     "clamp-half-2in",
     14,
     "seven joints, two halves each"
    ],
    [
     null,
     "socket-head-cap-screws-metric",
     "shcs-m5x30",
     14,
     "clamp bolts"
    ],
    [
     null,
     "hex-nuts-metric",
     "nut-m5",
     16,
     "clamp nuts (14), hanger bar (2)"
    ],
    [
     null,
     "tri-clamp-clamp-in-bearing-plate",
     "bearing-plate-2in-623",
     2,
     "one in each branch, spigot inward"
    ],
    [
     null,
     "ball-bearings-metric",
     "bearing-623",
     8,
     "bearing plates (4), con-rod eyes (4)"
    ],
    [
     null,
     "tri-clamp-cross-crank-webs",
     "inner-crank-web-hub-r6",
     2,
     "−X on the displacer pin side, +X on the diaphragm pin"
    ],
    [
     null,
     "tri-clamp-cross-crank-webs",
     "inner-crank-web-link-r6",
     1,
     "between the two pins, 90° apart"
    ],
    [
     null,
     "dowel-pins-metric",
     "dowel-3x12",
     2,
     "displacer crank pin, displacer clevis pin"
    ],
    [
     null,
     "dowel-pins-metric",
     "dowel-3x16",
     1,
     "diaphragm crank pin"
    ],
    [
     null,
     "dowel-pins-metric",
     "dowel-3x10",
     1,
     "crosshead pin"
    ],
    [
     null,
     "connecting-rods-623",
     "conrod-40",
     1,
     "displacer, in its clevis gap"
    ],
    [
     null,
     "connecting-rods-623",
     "conrod-60",
     1,
     "diaphragm, beside the displacer clevis"
    ],
    [
     null,
     "rod-clevises",
     "rod-clevis-3mm",
     1,
     "on the displacer rod"
    ],
    [
     null,
     "stirling-crankshafts",
     "crankshaft-3x80",
     1,
     "+X crankshaft: hub web to the pocket flywheel"
    ],
    [
     null,
     "displacer-rods",
     "rod-3x100",
     1,
     "−X crankshaft: hub web to the pocket flywheel"
    ],
    [
     null,
     "tri-clamp-crankcase-flywheel",
     "crank-flywheel-44x12-b3",
     2,
     "one on +X, one on −X outboard of the crank gear"
    ],
    [
     null,
     "tri-clamp-crankcase-flywheel",
     "pocket-flywheel-42x8-b3",
     2,
     "one on each shaft end, in the bearing plate's pocket"
    ],
    [
     null,
     "tri-clamp-generator-step-up-gears",
     "crank-gear-m1-42t-b3",
     1,
     "on the −X crankshaft beside the crank"
    ],
    [
     null,
     "tri-clamp-generator-step-up-gears",
     "pinion-m1-15t-b6",
     1,
     "on the motor shaft, 2.8 : 1"
    ],
    [
     null,
     "gimbal-motor-2208-envelope",
     "gimbal-motor-2208-envelope",
     1,
     "the generator: 2208 gimbal-class outrunner, KV 128, envelope at its published size"
    ],
    [
     null,
     "tri-clamp-generator-step-up-gears",
     "pinion-adaptor-2208",
     1,
     "bolted to the motor's rotor top; carries the pinion"
    ],
    [
     null,
     "socket-head-cap-screws-metric",
     "shcs-m2x4",
     4,
     "adaptor to the rotor top"
    ],
    [
     null,
     "countersunk-screws-metric",
     "csk-m3x6",
     4,
     "motor base to the mount face, heads flush"
    ],
    [
     null,
     "shaft-spacers",
     "spacer-3mm-t1",
     6,
     "each side: hub web to flywheel or gear, flywheel to inner 623, outer 623 to pocket flywheel"
    ],
    [
     null,
     "set-screws-metric",
     "set-m3x3",
     5,
     "hub webs (2), pocket flywheels (2), pinion (M3 × 3: ends inside the tooth root)"
    ],
    [
     null,
     "set-screws-metric",
     "set-m3x4",
     2,
     "displacer cap, rod clevis"
    ],
    [
     null,
     "set-screws-metric",
     "set-m3x10",
     3,
     "flywheel discs and crank gear, down their radial holes"
    ],
    [
     null,
     "spool-hanger-collars",
     "hanger-2in-tab",
     1,
     "on the cross's lower run, bar to the wall"
    ],
    [
     null,
     "spool-hanger-collars",
     "hanger-2in-plain",
     1,
     "closes the hanger"
    ],
    [
     null,
     "socket-head-cap-screws-metric",
     "shcs-m4x20",
     2,
     "hanger ears"
    ],
    [
     null,
     "socket-head-cap-screws-metric",
     "shcs-m5x25",
     2,
     "hanger bar through the wall"
    ]
   ]
  }
 },
 "sheet_text": "Build list: Tri-clamp sealed diaphragm generator, 2 in — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/list-tri-clamp-sealed-diaphragm-generator/  (CC BY 4.0)\nBasis: Every part is a free STEP/STL on this site or a standard part with its own page; quantities are the full count, every screw, nut, pin, gasket and clamp.\nCatalog version: 2026-10-20\n\nSizes: see table below\n- A sealed, pressurised gamma Stirling generator in 2 in tri-clamp: a plain closed-end cup over a torch, a power membrane between the working space and a sealed cross, and a 2208 gimbal motor geared to the crank inside the cross, its leads out through a sealed pass-through.\n- Numbers: Membrane 2 in at 12 mm: 11.33 mL swept · displacer Ø46 × 120 at 12 mm: 21.3 mL · dead volume 52.0 mL · swept / dead 0.218 · charge 2 bar gauge · Schmidt (600–700 K / 320 K): ±0.49–0.55 bar, 0.57–0.69 J per cycle · at 900 rpm about 4–8 W at the crank (West / Beale); 2208 gimbal generator at 2520 rpm, 19.7 V open circuit, about 2.1–5.5 W at 14–18 V out of 4–8 W at the crank\n\nsubsystem  object  parts  qty  note\nNone  tri-clamp-sealed-generator-frame  sealed-generator-frame-2in  1  base, wall, gussets\nNone  tri-clamp-torch-stand  torch-stand-40  1  on the base under the hot head, post toward +Y\nNone  socket-head-cap-screws-metric  shcs-m4x10  5  torch stand (2) and shroud feet (3) to the base\nNone  set-screws-metric  set-m4x10  3  centre the torch head in the stand ring\nNone  tri-clamp-burner-shroud  burner-shroud-2in  1  round the hot end, on its three feet\nNone  tri-clamp-cups  cup-2in-150  1  the hot end: a plain closed-end 2 in × 150 spool, face up; the displacer inside\nNone  tri-clamp-hot-fin-sleeve  hot-fin-sleeve-2in-80x9  1  optional heat exchanger: slides over the cup's closed end inside the shroud; without it the engine runs with less power\nNone  set-screws-metric  set-m4x4  3  optional: hold the fin sleeve (only with the sleeve)\nNone  tri-clamp-jacket-shell  jacket-half-2in-56  2  optional heat exchanger: round the cup under the clamp, the fill is the builder's choice; or cool the cold end any other way\nNone  tri-clamp-jacket-shell  jacket-port-cap  2  optional: one per jacket half (only with the jacket)\nNone  socket-head-cap-screws-metric  shcs-m4x30  4  optional: jacket ears (only with the jacket)\nNone  hex-nuts-metric  nut-m4  4  optional: jacket ears (only with the jacket)\nNone  hex-nuts-metric  nut-m4  2  hanger ears\nNone  tri-clamp-displacer  displacer-shell-2in-120  1  Ø46 × 120, 0.75 radial gap, 12 stroke\nNone  tri-clamp-displacer  displacer-cap-2in  1  closes the shell, holds the rod\nNone  stirling-crankshafts  crankshaft-3x60  1  displacer rod (Ø3 × 60), through the membrane and the crosshead's guide\nNone  tri-clamp-through-rod-membrane  membrane-2in-hole5  1  clamped between the hot cup and the cross, in place of a gasket\nNone  tri-clamp-diaphragm-crosshead  crosshead-2in-p29.25  1  crankcase side of the membrane: Ø3 guide (the bleed), con-rod pin on its arm\nNone  tri-clamp-diaphragm-crosshead  backing-2in-m2-tapped  1  working side of the membrane, M2 tapped\nNone  socket-head-cap-screws-metric  shcs-m2x6  3  heads on the crosshead, into the backing disc\nNone  sanitary-clamp-crosses  cross-2in  1  the crankcase: run vertical, branches along the crankshaft\nNone  tri-clamp-motor-mount-plate  motor-mount-plate-2in-2208  1  on the top of the cross; the motor hangs from it\nNone  tri-clamp-port-cap  port-cap-2in-4x-npt18  1  on the motor-mount plate\nNone  npt-thread-envelopes  npt-1-8-male  4  the 1/8 NPT stems of the fill valve, the pressure gauge, the relief valve and the sealed electrical pass-through (the bodies are the builder's choice)\nNone  tri-clamp-end-cap  tc-cap-2in-flat  2  close the two bearing plates\nNone  tri-clamp-gasket  tc-gasket-2in  6  cross–mount plate, mount plate–port cap, two cross–bearing plate, two bearing plate–end cap\nNone  tri-clamp-clamps  clamp-half-2in  14  seven joints, two halves each\nNone  socket-head-cap-screws-metric  shcs-m5x30  14  clamp bolts\nNone  hex-nuts-metric  nut-m5  16  clamp nuts (14), hanger bar (2)\nNone  tri-clamp-clamp-in-bearing-plate  bearing-plate-2in-623  2  one in each branch, spigot inward\nNone  ball-bearings-metric  bearing-623  8  bearing plates (4), con-rod eyes (4)\nNone  tri-clamp-cross-crank-webs  inner-crank-web-hub-r6  2  −X on the displacer pin side, +X on the diaphragm pin\nNone  tri-clamp-cross-crank-webs  inner-crank-web-link-r6  1  between the two pins, 90° apart\nNone  dowel-pins-metric  dowel-3x12  2  displacer crank pin, displacer clevis pin\nNone  dowel-pins-metric  dowel-3x16  1  diaphragm crank pin\nNone  dowel-pins-metric  dowel-3x10  1  crosshead pin\nNone  connecting-rods-623  conrod-40  1  displacer, in its clevis gap\nNone  connecting-rods-623  conrod-60  1  diaphragm, beside the displacer clevis\nNone  rod-clevises  rod-clevis-3mm  1  on the displacer rod\nNone  stirling-crankshafts  crankshaft-3x80  1  +X crankshaft: hub web to the pocket flywheel\nNone  displacer-rods  rod-3x100  1  −X crankshaft: hub web to the pocket flywheel\nNone  tri-clamp-crankcase-flywheel  crank-flywheel-44x12-b3  2  one on +X, one on −X outboard of the crank gear\nNone  tri-clamp-crankcase-flywheel  pocket-flywheel-42x8-b3  2  one on each shaft end, in the bearing plate's pocket\nNone  tri-clamp-generator-step-up-gears  crank-gear-m1-42t-b3  1  on the −X crankshaft beside the crank\nNone  tri-clamp-generator-step-up-gears  pinion-m1-15t-b6  1  on the motor shaft, 2.8 : 1\nNone  gimbal-motor-2208-envelope  gimbal-motor-2208-envelope  1  the generator: 2208 gimbal-class outrunner, KV 128, envelope at its published size\nNone  tri-clamp-generator-step-up-gears  pinion-adaptor-2208  1  bolted to the motor's rotor top; carries the pinion\nNone  socket-head-cap-screws-metric  shcs-m2x4  4  adaptor to the rotor top\nNone  countersunk-screws-metric  csk-m3x6  4  motor base to the mount face, heads flush\nNone  shaft-spacers  spacer-3mm-t1  6  each side: hub web to flywheel or gear, flywheel to inner 623, outer 623 to pocket flywheel\nNone  set-screws-metric  set-m3x3  5  hub webs (2), pocket flywheels (2), pinion (M3 × 3: ends inside the tooth root)\nNone  set-screws-metric  set-m3x4  2  displacer cap, rod clevis\nNone  set-screws-metric  set-m3x10  3  flywheel discs and crank gear, down their radial holes\nNone  spool-hanger-collars  hanger-2in-tab  1  on the cross's lower run, bar to the wall\nNone  spool-hanger-collars  hanger-2in-plain  1  closes the hanger\nNone  socket-head-cap-screws-metric  shcs-m4x20  2  hanger ears\nNone  socket-head-cap-screws-metric  shcs-m5x25  2  hanger bar through the wall\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/\n\nXem Studio scan: not planned; the official CAD above covers it.\nAPI: https://xemstudio.com/api/geometry?object=list-tri-clamp-sealed-diaphragm-generator\n",
 "sources": [
  {
   "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": "not-scanned",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "tri-clamp-hot-fin-sleeve",
  "tri-clamp-cups",
  "tri-clamp-burner-shroud",
  "tri-clamp-through-rod-membrane",
  "tri-clamp-diaphragm-crosshead",
  "tri-clamp-clamp-in-bearing-plate",
  "tri-clamp-generator-step-up-gears",
  "tri-clamp-motor-mount-plate",
  "tri-clamp-crankcase-flywheel",
  "tri-clamp-port-cap",
  "tri-clamp-sealed-generator-frame",
  "list-tri-clamp-cross-diaphragm-gamma"
 ],
 "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": [],
 "faq": [
  {
   "q": "What parts do I need for the tri-clamp sealed diaphragm generator?",
   "a": "57 parts, every one a free STEP/STL on this site; see the table and the build order on this page."
  },
  {
   "q": "How much electricity does it make?",
   "a": "The engine should give about 4–8 W at the crank at 900 rpm (West and Beale numbers 3.9–7.7 W). The 2208 gimbal motor turns 2520 rpm and makes 19.7 V open circuit; after the gears (1–3 %), its drag (0.3–1.6 W, estimated) and its 14.4 Ω winding, about 2.1–5.5 W reaches the leads at 14–18 V and 0.12–0.39 A: a bridge rectifier and a buck converter rated for the open-circuit voltage make USB 5 V from it."
  },
  {
   "q": "Why this motor and 2.8 : 1?",
   "a": "In a generator the winding loss is (torque / motor constant)², and the gears divide the torque, so the most gearing that fits wins. The motor can lies over the crank and the crank gear has to fit the 2 in bore: 42 : 15 at module 1 is the most that fits a Ø27.5 can. Of the low-KV motors with published size, KV and resistance that fit, the 2208 gives the most watts at a voltage a buck converter takes; the 2212 drone motor gives a little more power but only about 2.5 V. Driven straight from the crank (1 : 1) any of them would turn most of the power into winding heat."
  },
  {
   "q": "What pressure, and how do I charge it?",
   "a": "2 bar gauge of air or helium through the fill valve on the port cap. Charge slowly: the working space fills only through the bleed along the displacer rod (time constant about 8 min at 5 µm clearance, 64 s at 10 µm), and until the two sides meet, the membrane carries the difference. Let the gauge settle between small steps; let it down the same way."
  },
  {
   "q": "Air or helium?",
   "a": "The Schmidt work per cycle is the same at the same pressure and temperatures. Helium flows through the 0.75 mm gap and the bleed with less loss and lets the engine turn faster, which raises the generator's voltage."
  },
  {
   "q": "Why does the displacer rod pass through the membrane?",
   "a": "The working space and the crankcase meet at one joint, the membrane's. The displacer sits under the membrane, so its rod comes up through the membrane's centre and guides in the crosshead hub, whose bore is also the bleed."
  },
  {
   "q": "Where can the gas leak out?",
   "a": "There is no shaft seal. Every joint is a clamped gasket, the clamped membrane, or a threaded port; the motor leads leave through a sealed pass-through in one of the ports."
  },
  {
   "q": "Is the flywheel big enough?",
   "a": "The cycle swings about 0.16 J. The two discs, the crank gear, the two pocket flywheels and the motor's can (counted 7.8 times through the gears) hold the speed swing to about 12–27 % at 900 rpm (disc density 7.8 to 2.7 g/cm³); it falls with the square of the speed."
  }
 ],
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 "markdown": "https://xemstudio.com/objects/list-tri-clamp-sealed-diaphragm-generator/index.md"
}