{
 "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-htd-10in",
 "name": "Build list: HTD engine, 10 in tri-clamp (high-temperature-differential flat engine)",
 "kind": "list",
 "category": "Stirling engines",
 "group": "Guide",
 "year": null,
 "question": "What parts do I need to build the HTD engine, 10 in tri-clamp (high-temperature-differential flat engine)?",
 "tags": [
  "list",
  "build",
  "stirling",
  "long earth society",
  "tri-clamp",
  "htd",
  "gamma",
  "sealed",
  "helium",
  "generator",
  "burner"
 ],
 "aliases": [
  "htd stirling engine",
  "big tri clamp stirling",
  "10 inch tri clamp stirling",
  "propane stirling engine",
  "flat plate stirling hot",
  "helium stirling engine build"
 ],
 "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-htd-10in/",
 "sheet_txt": "https://xemstudio.com/objects/list-htd-10in/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 big flat gamma Stirling for a propane burner: a Ø240 displacer in a 10 in welded-bottom cup, a 48 mm power piston in a bored 2 in spool on the cold cap, a 3 in cross crankcase, a Ø400 flywheel and a geared generator; sealed and charged with helium.",
   "Numbers: Displacer Ø240 × 40, 8 stroke: 362 mL swept · power piston Ø48.00 × 40: 72.4 mL · dead volume 405 mL · swept/dead 0.179 · Schmidt at 650 / 350 K: 1.47 J per cycle in air at 1 bar, 7.3 J in helium at 5 bar abs · heat-transfer-limited best: air 0.39 W at the shaft near 60 rpm, helium 3.9–4.7 W near 150 rpm · generator 3.4–4.2 W at 11 V (helium) · charge 4 bar gauge helium, relief 6 bar gauge · hot face ≤ 450 °C"
  ],
  "table": {
   "columns": [
    "subsystem",
    "object",
    "parts",
    "qty",
    "note"
   ],
   "rows": [
    [
     null,
     "htd-burner-stand-10in",
     "burner-stand-10in",
     1,
     "on the bench over the burner; its ring carries the 10 in clamp"
    ],
    [
     null,
     "htd-burner-shroud-10in",
     "burner-shroud-10in",
     1,
     "optional heat exchanger: round the cup's floor, tabs to the legs"
    ],
    [
     null,
     "socket-head-cap-screws-metric",
     "shcs-m5x20",
     3,
     "optional: shroud tabs to the legs"
    ],
    [
     null,
     "htd-hot-cup-10in",
     "hot-cup-10in-60.4",
     1,
     "face up, through the ring; the displacer inside"
    ],
    [
     null,
     "htd-displacers-10in",
     "displacer-240x40-rod6",
     1,
     "Ø240 × 40, 8 stroke, 1.5 from floor and ceiling at the ends"
    ],
    [
     null,
     "htd-displacer-rods",
     "displacer-rod-6x356.7",
     1,
     "M6 into the displacer, up through guide, spool and piston to the clevis"
    ],
    [
     null,
     "sanitary-clamp-gaskets-10-12in",
     "gasket-10in",
     1,
     "cup to cold cap"
    ],
    [
     null,
     "sanitary-clamp-bolted-clamps-10-12in",
     "clamp-half-10in-m8",
     2,
     "the 10 in joint, resting on the stand's ring"
    ],
    [
     null,
     "socket-head-cap-screws-metric",
     "shcs-m8x40",
     2,
     "10 in clamp bolts"
    ],
    [
     null,
     "hex-nuts-metric",
     "nut-m8",
     2,
     "in the 10 in clamp's traps"
    ],
    [
     null,
     "htd-cold-caps-10in",
     "cold-cap-10in-main",
     1,
     "2 in ferrule up"
    ],
    [
     null,
     "npt-thread-envelopes",
     "npt-1-8-male",
     1,
     "the working-space gauge's 1/8 NPT stem in the cap's boss (the gauge body is the builder's choice)"
    ],
    [
     null,
     "htd-water-tray-10in",
     "water-tray-10in",
     1,
     "optional heat exchanger: on the cap's flat top round the ferrule"
    ],
    [
     null,
     "tri-clamp-gasket",
     "tc-gasket-2in",
     2,
     "cap ferrule to bored spool, bored spool to reducer"
    ],
    [
     null,
     "tri-clamp-clamps",
     "clamp-half-2in",
     4,
     "two 2 in joints"
    ],
    [
     null,
     "htd-bored-power-spool",
     "spool-2in-5in-bored-48.00",
     1,
     "the power cylinder"
    ],
    [
     null,
     "htd-power-pistons",
     "piston-48-rod6",
     1,
     "crown down, cheeks up"
    ],
    [
     null,
     "sanitary-clamp-reducers",
     "reducer-concentric-3inx2in",
     1,
     "small end down"
    ],
    [
     null,
     "sanitary-clamp-gaskets",
     "gasket-3in",
     4,
     "reducer to cross, cross to port cap, the two branch caps"
    ],
    [
     null,
     "tri-clamp-clamps",
     "clamp-half-3in",
     8,
     "four 3 in joints"
    ],
    [
     null,
     "socket-head-cap-screws-metric",
     "shcs-m5x30",
     12,
     "2 and 3 in clamp bolts"
    ],
    [
     null,
     "hex-nuts-metric",
     "nut-m5",
     15,
     "clamp nuts (12), shroud tabs (3, optional)"
    ],
    [
     null,
     "sanitary-clamp-crosses",
     "cross-3in",
     1,
     "the crankcase: run vertical, branches along the crankshaft"
    ],
    [
     null,
     "htd-crankcase-caps-3in",
     "port-cap-3in-3x-npt14",
     1,
     "top of the cross: fill valve, gauge, relief valve"
    ],
    [
     null,
     "npt-thread-envelopes",
     "npt-1-4-male",
     3,
     "the 1/4 NPT stems of the fill valve, gauge and relief valve (bodies are the builder's choice)"
    ],
    [
     null,
     "htd-crankcase-caps-3in",
     "bearing-cap-3in-blind-6001",
     1,
     "−X branch"
    ],
    [
     null,
     "htd-crankcase-caps-3in",
     "seal-cap-3in-6001-seal12",
     1,
     "+X branch: the shaft leaves here"
    ],
    [
     null,
     "ball-bearings-metric",
     "bearing-6001",
     3,
     "blind cap (1), seal cap (2)"
    ],
    [
     null,
     "radial-shaft-seal-12x22x7",
     "shaft-seal-12x22x7",
     1,
     "in the seal cap's outer housing; rated for the relief pressure"
    ],
    [
     null,
     "htd-crank-linkage",
     "shaft-12x76",
     1,
     "−X shaft"
    ],
    [
     null,
     "htd-crank-linkage",
     "shaft-12x210",
     1,
     "+X shaft"
    ],
    [
     null,
     "htd-crank-linkage",
     "crank-web-r8-b12",
     1,
     "displacer throw"
    ],
    [
     null,
     "htd-crank-linkage",
     "crank-web-link-r8-r20",
     1,
     "between the two con-rods"
    ],
    [
     null,
     "htd-crank-linkage",
     "crank-web-r20-b12",
     1,
     "piston throw"
    ],
    [
     null,
     "set-screws-metric",
     "set-m4x6",
     2,
     "web hubs"
    ],
    [
     null,
     "dowel-pins-metric",
     "dowel-5x16",
     4,
     "two crank pins, the piston pin, the clevis pin"
    ],
    [
     null,
     "ball-bearings-metric",
     "bearing-625",
     4,
     "con-rod eyes"
    ],
    [
     null,
     "htd-crank-linkage",
     "conrod-60-625",
     1,
     "displacer"
    ],
    [
     null,
     "htd-crank-linkage",
     "conrod-237-625",
     1,
     "piston"
    ],
    [
     null,
     "htd-crank-linkage",
     "rod-clevis-6-pin5",
     1,
     "on top of the displacer rod"
    ],
    [
     null,
     "set-screws-metric",
     "set-m4x4",
     1,
     "clevis to rod"
    ],
    [
     null,
     "htd-generator-drive",
     "gear-m1-210t-b12",
     1,
     "on the +X shaft outside the seal cap"
    ],
    [
     null,
     "set-screws-metric",
     "set-m4x8",
     1,
     "gear hub"
    ],
    [
     null,
     "htd-flywheel-400",
     "flywheel-400-b12",
     1,
     "on the +X shaft end"
    ],
    [
     null,
     "set-screws-metric",
     "set-m6x16",
     2,
     "flywheel hub"
    ],
    [
     null,
     "htd-generator-drive",
     "motor-bracket-2208-3in",
     1,
     "on the seal cap's outer face"
    ],
    [
     null,
     "socket-head-cap-screws-metric",
     "shcs-m4x12",
     3,
     "bracket to the seal cap"
    ],
    [
     null,
     "gimbal-motor-2208-envelope",
     "gimbal-motor-2208-envelope",
     1,
     "the generator: 2208 gimbal-class outrunner (KV 128), envelope at its published size"
    ],
    [
     null,
     "countersunk-screws-metric",
     "csk-m3x8",
     4,
     "motor base to the bracket, heads in the countersinks"
    ],
    [
     null,
     "tri-clamp-generator-step-up-gears",
     "pinion-adaptor-2208",
     1,
     "on the motor's rotor top"
    ],
    [
     null,
     "socket-head-cap-screws-metric",
     "shcs-m2x4",
     4,
     "adaptor to the rotor"
    ],
    [
     null,
     "tri-clamp-generator-step-up-gears",
     "pinion-m1-15t-b6",
     1,
     "meshes with the 210 T gear, 14 : 1"
    ],
    [
     null,
     "set-screws-metric",
     "set-m3x3",
     1,
     "pinion grub"
    ]
   ]
  }
 },
 "sheet_text": "Build list: HTD engine, 10 in tri-clamp (high-temperature-differential flat engine) — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/list-htd-10in/  (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 big flat gamma Stirling for a propane burner: a Ø240 displacer in a 10 in welded-bottom cup, a 48 mm power piston in a bored 2 in spool on the cold cap, a 3 in cross crankcase, a Ø400 flywheel and a geared generator; sealed and charged with helium.\n- Numbers: Displacer Ø240 × 40, 8 stroke: 362 mL swept · power piston Ø48.00 × 40: 72.4 mL · dead volume 405 mL · swept/dead 0.179 · Schmidt at 650 / 350 K: 1.47 J per cycle in air at 1 bar, 7.3 J in helium at 5 bar abs · heat-transfer-limited best: air 0.39 W at the shaft near 60 rpm, helium 3.9–4.7 W near 150 rpm · generator 3.4–4.2 W at 11 V (helium) · charge 4 bar gauge helium, relief 6 bar gauge · hot face ≤ 450 °C\n\nsubsystem  object  parts  qty  note\nNone  htd-burner-stand-10in  burner-stand-10in  1  on the bench over the burner; its ring carries the 10 in clamp\nNone  htd-burner-shroud-10in  burner-shroud-10in  1  optional heat exchanger: round the cup's floor, tabs to the legs\nNone  socket-head-cap-screws-metric  shcs-m5x20  3  optional: shroud tabs to the legs\nNone  htd-hot-cup-10in  hot-cup-10in-60.4  1  face up, through the ring; the displacer inside\nNone  htd-displacers-10in  displacer-240x40-rod6  1  Ø240 × 40, 8 stroke, 1.5 from floor and ceiling at the ends\nNone  htd-displacer-rods  displacer-rod-6x356.7  1  M6 into the displacer, up through guide, spool and piston to the clevis\nNone  sanitary-clamp-gaskets-10-12in  gasket-10in  1  cup to cold cap\nNone  sanitary-clamp-bolted-clamps-10-12in  clamp-half-10in-m8  2  the 10 in joint, resting on the stand's ring\nNone  socket-head-cap-screws-metric  shcs-m8x40  2  10 in clamp bolts\nNone  hex-nuts-metric  nut-m8  2  in the 10 in clamp's traps\nNone  htd-cold-caps-10in  cold-cap-10in-main  1  2 in ferrule up\nNone  npt-thread-envelopes  npt-1-8-male  1  the working-space gauge's 1/8 NPT stem in the cap's boss (the gauge body is the builder's choice)\nNone  htd-water-tray-10in  water-tray-10in  1  optional heat exchanger: on the cap's flat top round the ferrule\nNone  tri-clamp-gasket  tc-gasket-2in  2  cap ferrule to bored spool, bored spool to reducer\nNone  tri-clamp-clamps  clamp-half-2in  4  two 2 in joints\nNone  htd-bored-power-spool  spool-2in-5in-bored-48.00  1  the power cylinder\nNone  htd-power-pistons  piston-48-rod6  1  crown down, cheeks up\nNone  sanitary-clamp-reducers  reducer-concentric-3inx2in  1  small end down\nNone  sanitary-clamp-gaskets  gasket-3in  4  reducer to cross, cross to port cap, the two branch caps\nNone  tri-clamp-clamps  clamp-half-3in  8  four 3 in joints\nNone  socket-head-cap-screws-metric  shcs-m5x30  12  2 and 3 in clamp bolts\nNone  hex-nuts-metric  nut-m5  15  clamp nuts (12), shroud tabs (3, optional)\nNone  sanitary-clamp-crosses  cross-3in  1  the crankcase: run vertical, branches along the crankshaft\nNone  htd-crankcase-caps-3in  port-cap-3in-3x-npt14  1  top of the cross: fill valve, gauge, relief valve\nNone  npt-thread-envelopes  npt-1-4-male  3  the 1/4 NPT stems of the fill valve, gauge and relief valve (bodies are the builder's choice)\nNone  htd-crankcase-caps-3in  bearing-cap-3in-blind-6001  1  −X branch\nNone  htd-crankcase-caps-3in  seal-cap-3in-6001-seal12  1  +X branch: the shaft leaves here\nNone  ball-bearings-metric  bearing-6001  3  blind cap (1), seal cap (2)\nNone  radial-shaft-seal-12x22x7  shaft-seal-12x22x7  1  in the seal cap's outer housing; rated for the relief pressure\nNone  htd-crank-linkage  shaft-12x76  1  −X shaft\nNone  htd-crank-linkage  shaft-12x210  1  +X shaft\nNone  htd-crank-linkage  crank-web-r8-b12  1  displacer throw\nNone  htd-crank-linkage  crank-web-link-r8-r20  1  between the two con-rods\nNone  htd-crank-linkage  crank-web-r20-b12  1  piston throw\nNone  set-screws-metric  set-m4x6  2  web hubs\nNone  dowel-pins-metric  dowel-5x16  4  two crank pins, the piston pin, the clevis pin\nNone  ball-bearings-metric  bearing-625  4  con-rod eyes\nNone  htd-crank-linkage  conrod-60-625  1  displacer\nNone  htd-crank-linkage  conrod-237-625  1  piston\nNone  htd-crank-linkage  rod-clevis-6-pin5  1  on top of the displacer rod\nNone  set-screws-metric  set-m4x4  1  clevis to rod\nNone  htd-generator-drive  gear-m1-210t-b12  1  on the +X shaft outside the seal cap\nNone  set-screws-metric  set-m4x8  1  gear hub\nNone  htd-flywheel-400  flywheel-400-b12  1  on the +X shaft end\nNone  set-screws-metric  set-m6x16  2  flywheel hub\nNone  htd-generator-drive  motor-bracket-2208-3in  1  on the seal cap's outer face\nNone  socket-head-cap-screws-metric  shcs-m4x12  3  bracket to the seal cap\nNone  gimbal-motor-2208-envelope  gimbal-motor-2208-envelope  1  the generator: 2208 gimbal-class outrunner (KV 128), envelope at its published size\nNone  countersunk-screws-metric  csk-m3x8  4  motor base to the bracket, heads in the countersinks\nNone  tri-clamp-generator-step-up-gears  pinion-adaptor-2208  1  on the motor's rotor top\nNone  socket-head-cap-screws-metric  shcs-m2x4  4  adaptor to the rotor\nNone  tri-clamp-generator-step-up-gears  pinion-m1-15t-b6  1  meshes with the 210 T gear, 14 : 1\nNone  set-screws-metric  set-m3x3  1  pinion grub\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Wiley / Ohio University (I. Urieli): Urieli & Berchowitz, Stirling Cycle Engine Analysis (Adam Hilger, 1984): isothermal (Schmidt) and simple analyses; course pages — book, web — analysis methods are facts [verify license at link] — https://www.ohio.edu/mechanical/stirling/isothermal/Schmidt.html\n- J. R. Senft: An Introduction to Low Temperature Differential Stirling Engines (Moriya Press, 1996); Mechanical Efficiency of Heat Engines (Cambridge, 2007): forced work and the fundamental efficiency theorem — book — methods are facts [verify license at link] — https://www.cambridge.org/core/books/mechanical-efficiency-of-heat-engines/\n- Steel & O'Brien: Sanitary products catalog 2024: 16AMP end caps 10 / 12 in (A 0.480, B 10.570 / 12.570 in); L14AM7 ferrules 1.500 in; clamp ratings 13MHHM, 13MHP, 13ASME — PDF — publisher's catalogue; dimensions cited, nothing copied — https://www.steelobrien.com/wp-content/uploads/2024/03/Sanitary-2024-FINAL.pdf\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-htd-10in\n",
 "sources": [
  {
   "publisher": "Wiley / Ohio University (I. Urieli)",
   "title": "Urieli & Berchowitz, Stirling Cycle Engine Analysis (Adam Hilger, 1984): isothermal (Schmidt) and simple analyses; course pages",
   "url": "https://www.ohio.edu/mechanical/stirling/isothermal/Schmidt.html",
   "formats": [
    "book",
    "web"
   ],
   "license": "analysis methods are facts",
   "license_verified": false,
   "hosted": false
  },
  {
   "publisher": "J. R. Senft",
   "title": "An Introduction to Low Temperature Differential Stirling Engines (Moriya Press, 1996); Mechanical Efficiency of Heat Engines (Cambridge, 2007): forced work and the fundamental efficiency theorem",
   "url": "https://www.cambridge.org/core/books/mechanical-efficiency-of-heat-engines/",
   "formats": [
    "book"
   ],
   "license": "methods are facts",
   "license_verified": false,
   "hosted": false
  },
  {
   "publisher": "Steel & O'Brien",
   "title": "Sanitary products catalog 2024: 16AMP end caps 10 / 12 in (A 0.480, B 10.570 / 12.570 in); L14AM7 ferrules 1.500 in; clamp ratings 13MHHM, 13MHP, 13ASME",
   "url": "https://www.steelobrien.com/wp-content/uploads/2024/03/Sanitary-2024-FINAL.pdf",
   "formats": [
    "PDF"
   ],
   "license": "publisher's catalogue; dimensions cited, nothing copied",
   "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": "not-scanned",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "htd-hot-cup-10in",
  "htd-cold-caps-10in",
  "sanitary-clamp-bolted-clamps-10-12in",
  "htd-crank-linkage",
  "htd-flywheel-400"
 ],
 "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": "How much power does the 10 in HTD make?",
   "a": "In air at 1 bar about 0.39 W at the shaft near 60 rpm; charged with helium at 4 bar gauge about 3.9–4.7 W near 150 rpm, 3.4–4.2 W of it out of the generator."
  },
  {
   "q": "What pressure is it charged to?",
   "a": "4 bar gauge of helium, relief valve at 6 bar gauge. The 10 in joint then carries 21–32 kN; every clamp, gasket and fitting has to be rated above 6 bar at its temperature."
  },
  {
   "q": "Why is the hot face a welded cup?",
   "a": "So there is no gasket or clamp in the flame: the only joint is at the cold cap."
  },
  {
   "q": "Why so slow?",
   "a": "No regenerator, and the gas heats by conduction across its layer; past a couple of hundred rpm the gas temperatures close up and the friction wins."
  }
 ],
 "files_license": null,
 "offers": [],
 "markdown": "https://xemstudio.com/objects/list-htd-10in/index.md"
}