# Build list: Tri-clamp twin walking-beam gamma generator, 2 in, chargeable

> What parts do I need to build a Tri-clamp twin walking-beam gamma generator, 2 in, chargeable?

- Category: Stirling engines › Assembled engines
- Kind: List / guide
- 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.
- Page: https://xemstudio.com/objects/list-tri-clamp-twin-walking-beam-gamma/ · JSON: https://xemstudio.com/api/geometry?object=list-tri-clamp-twin-walking-beam-gamma · Plain text: https://xemstudio.com/objects/list-tri-clamp-twin-walking-beam-gamma/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** True size, with no printing tolerance added.

## Notes

- Two walking-beam tee units side by side on one crank, a quarter turn apart: each with its own closed hot spool over its own burner, its own tee, power cylinder, bounce spool and beam; one crankshaft, one Ø200 flywheel, one belted generator, one base.
- Numbers: Two walking-beam units on one crank, 90° apart · each: displacer Ø40 × 30, piston Ø48 × 36 · model shaft power: air 1 atm 4–9 W at 600 rpm; charged 5 bar gauge: air 12–59 W, helium 28–122 W at 1200 rpm · gas torque at 90°: 0.11–0.47 N·m (one unit -0.32–0.63) · 2208 generator: 1.0–7.1 W at 24–28 V at 1 atm

## Sizes

| subsystem | object | parts | qty | note |
|---|---|---|---|---|
| None | tri-clamp-twin-walking-beam-gamma-frame | twin-walking-beam-gamma-frame-2in | 1 | base, four cradles, two beam posts, crank uprights, generator bracket |
| None | tri-clamp-torch-stand | torch-stand-40 | 2 | under the shroud's inlet, post toward −Y |
| None | set-screws-metric | set-m4x10 | 6 | centre the torch head in the stand ring |
| None | socket-head-cap-screws-metric | shcs-m4x10 | 8 | torch stand (2), shroud feet (2) |
| None | tri-clamp-horizontal-burner-shroud | burner-shroud-2in-horizontal | 2 | round the fins |
| None | tri-clamp-closed-hot-spool-bored | hot-spool-2in-152.4-closed-bored-48.00 | 2 | on the tee's −X run end |
| None | tri-clamp-ring-fin-sleeve | fin-sleeve-2in-9x76 | 2 | optional heat exchanger: slid over the closed end |
| None | tri-clamp-flow-water-jacket | water-jacket-half-2in-48-flow | 4 | optional heat exchanger: round the cold end, hose spigots up and down |
| None | socket-head-cap-screws-metric | shcs-m4x25 | 8 | optional: water-jacket ears |
| None | hex-nuts-metric | nut-m4 | 8 | optional: water-jacket ears |
| None | stirling-annular-screen-stack | screen-stack-48x42x40-50mesh | 2 | optional heat exchanger (with the liner): on the liner's neck |
| None | stirling-slotted-regenerator-liner | liner-2in-slotted-48-40 | 2 | optional heat exchanger (internal insert), pressed into the hot spool: without it the displacer runs in the Ø48.00 bore 4 mm clear, a plain annular-gap engine with far less power |
| None | stirling-clearance-seal-displacer | displacer-shell-38.5x98 | 2 | the shell |
| None | stirling-clearance-seal-displacer | displacer-cap-40-land | 2 | pressed into the shell; land in the liner bore |
| None | stirling-precision-rods | rod-6x315.4-m6 | 2 | displacer rod: through the run plug and the gland cap to its yoke |
| None | hex-nuts-metric | nut-m6 | 4 | lock nuts: displacer cold face, under the displacer yoke |
| None | sanitary-clamp-tees | tee-2in | 2 | equal tee: run along the engine, branch up |
| None | tri-clamp-tee-filler-plugs | tee-run-plug-2in-rod6 | 2 | in the run |
| None | tri-clamp-tee-filler-plugs | tee-branch-plug-2in | 2 | in the branch, on the run plug |
| None | tri-clamp-rod-gland-cap | gland-cap-2in-2x-6x10x10-3x-npt14 | 2 | +X run end: displacer-rod gland; fill, gauge, relief |
| None | sleeve-bushings | bushing-6x10x10 | 4 | in the displacer gland cap |
| None | tri-clamp-spool-bored-honed | spool-2in-3in-bored-48.00 | 2 | power cylinder, on the branch |
| None | stirling-clearance-seal-pistons | piston-48-gamma-m8 | 2 | Ø48.00, rod up |
| None | stirling-precision-rods | rod-8x304.85-m8 | 2 | piston rod |
| None | hex-nuts-metric | nut-m8 | 4 | lock nuts: piston boss, under the piston yoke |
| None | tri-clamp-spool-npt-bosses | spool-2in-6in-3x-npt14 | 2 | bounce space above the piston |
| None | tri-clamp-rod-gland-cap | gland-cap-2in-2x-8x12x20 | 2 | closes the bounce spool; the piston rod's gland |
| None | sleeve-bushings | bushing-8x12x20 | 4 | in the piston-rod gland cap |
| None | high-pressure-sanitary-clamps | hp-clamp-2in | 10 | hot spool–tee, tee–gland cap, tee–power spool, power–bounce spool, bounce spool–gland cap; rating above the 7 bar gauge relief setting (not drawn here) |
| None | tri-clamp-gasket | tc-gasket-2in | 10 | the five 2 in joints |
| None | npt-thread-envelopes | npt-1-4-male | 12 | 1/4 NPT stems: working-space fill, gauge, relief on the gland cap; bounce-space fill, gauge, relief (bodies are the builder's choice) |
| None | stirling-crosshead-yokes | yoke-rod6-m6 | 2 | displacer yoke, stub pin toward +Y |
| None | stirling-crosshead-yokes | yoke-rod8-m8 | 2 | piston yoke, stub pin toward +Y |
| None | dowel-pins-metric | dowel-5x20 | 4 | stub wrist pins |
| None | shaft-collars | collar-5mm | 6 | wrist pins (2), beam end B pin |
| None | shaft-collars | collar-6mm | 4 | crank pin, beam end A pin |
| None | set-screws-metric | set-m3x4 | 10 | 5 and 6 mm collars |
| None | stirling-walking-beam | walking-beam-158.07-131.73 | 2 | on the post's pivot |
| None | ball-bearings-metric | bearing-625 | 10 | beam pivot (2), small ends of the displacer con-rod and both links (3) |
| None | dowel-pins-metric | dowel-5x30 | 4 | beam pivot pin, beam end B pin |
| None | dowel-pins-metric | dowel-6x30 | 4 | crank pin, beam end A pin |
| None | stirling-conrods-626-625 | conrod-626-625-60 | 2 | link A: piston yoke to beam end A |
| None | stirling-conrods-626-625 | conrod-626-625-488.4 | 2 | link B: crank pin to beam end B |
| None | stirling-conrods-626-625 | conrod-626-625-100 | 2 | displacer |
| None | ball-bearings-metric | bearing-626 | 6 | big ends |
| None | stirling-built-up-crank-webs | crank-web-56x12-r15 | 2 | one overhung web per unit on the shared shaft, pins a quarter turn apart |
| None | stirling-precision-rods | shaft-8x91 | 1 | the shared crankshaft: both webs, flywheel and pulley |
| None | ball-bearings-metric | bearing-608 | 2 | crank uprights |
| None | nut-pocket-flywheels | flywheel-200-m12-b8 | 1 | outboard of the uprights |
| None | hex-nut-weights | nut-m12 | 18 | one in each rim pocket |
| None | set-screws-metric | set-m3x6 | 1 | flywheel hub |
| None | round-belt-generator-drive | crank-pulley-84-b8 | 1 | on the crankshaft's free end |
| None | set-screws-metric | set-m4x6 | 1 | crank-pulley hub |
| None | gimbal-motor-2208-envelope | gimbal-motor-2208-envelope | 1 | the generator: 2208 gimbal outrunner, KV 128, 14.4 Ω (envelope at its published size) |
| None | countersunk-screws-metric | csk-m3x6 | 4 | motor base to the bracket, heads flush |
| None | round-belt-generator-drive | generator-pulley-2208-pd13.33 | 1 | on the motor's rotor top |
| None | socket-head-cap-screws-metric | shcs-m2x6 | 4 | generator pulley to the rotor top |
| None | round-belt-generator-drive | round-belt-5-c130 | 1 | drawn on its pitch line) |

## Where the files are

- Long Earth Society: [Engine builds](https://longearthsociety.com/engineering/) — web, video — LES site

## Build order

1. Frame; two torch stands, two shrouds, four cradles.
2. Build each unit as the walking-beam gamma (unit 2 mirrored: its stub pins and links toward −Y).
3. Shaft through both uprights' 608s with the flywheel and the crank pulley between them; press the two webs on with their pins a quarter turn apart; con-rods and links onto the pins.
4. Generator, belt.

All printed STLs: https://xemstudio.com/objects/list-tri-clamp-twin-walking-beam-gamma/stl-list.txt

## Questions

**Why 90°?**

In the model it is the only phase where the summed gas torque stays positive over the whole turn (0.11–0.47 N·m at 1 atm).

**Why not join the two hot ends?**

Two working spaces out of phase would only push gas back and forth between them; each unit keeps its own.

**How much power?**

About twice one unit: 4–9 W at the crank at 600 rpm open to air in the model.

## Fits with

- [Build list: Tri-clamp walking-beam gamma generator, 2 in, chargeable](https://xemstudio.com/objects/list-tri-clamp-walking-beam-gamma/)
- [Frame for the tri-clamp twin walking-beam gamma](https://xemstudio.com/objects/tri-clamp-twin-walking-beam-gamma-frame/)
- [Round-belt generator drive: Ø84 crank pulley, 2208 generator pulley, Ø5 belts](https://xemstudio.com/objects/round-belt-generator-drive/)