# Build list: Tri-clamp charged beta, 2 in

> What parts do I need to build a Tri-clamp charged beta, 2 in?

- 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-charged-beta/ · JSON: https://xemstudio.com/api/geometry?object=list-tri-clamp-charged-beta · Plain text: https://xemstudio.com/objects/list-tri-clamp-charged-beta/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

- A standing beta that holds a charge: the same hot spool, liner, regenerator and displacer as the horizontal gamma, the bored power spool directly above them, coaxial rods, and a 3 in tee as a sealed crankcase with a shaft seal on the output.
- Numbers: Displacer Ø40 × 30 (37.7 mL) · piston Ø48 × 36 (64.1 mL net of the Ø6 rod) · 90° · dead 66.2 mL (swept/dead 0.97) · charge 5 bar gauge, relief 7 · crankcase buffer 1.52 L · model shaft power: air 17–40 W at 600 rpm, helium 36–82 W at 1200 rpm

## Sizes

| subsystem | object | parts | qty | note |
|---|---|---|---|---|
| None | tri-clamp-charged-beta-frame | charged-beta-frame-2in | 1 | base, wall, gussets |
| None | tri-clamp-torch-stand | torch-stand-40 | 1 | under the hot spool, post toward +Y |
| None | set-screws-metric | set-m4x10 | 3 | centre the torch head in the stand ring |
| None | socket-head-cap-screws-metric | shcs-m4x10 | 5 | torch stand (2), shroud feet (3) |
| None | tri-clamp-burner-shroud | burner-shroud-2in | 1 | round the fins |
| None | tri-clamp-closed-hot-spool-bored | hot-spool-2in-152.4-closed-bored-48.00 | 1 | face up, closed end in the shroud |
| None | tri-clamp-ring-fin-sleeve | fin-sleeve-2in-9x76 | 1 | optional heat exchanger: slid over the closed end |
| None | tri-clamp-flow-water-jacket | water-jacket-half-2in-48-flow | 2 | optional heat exchanger: round the cold end over the cooler zone, hose spigots toward ±Y |
| None | socket-head-cap-screws-metric | shcs-m4x25 | 4 | optional: water-jacket ears |
| None | hex-nuts-metric | nut-m4 | 4 | optional: water-jacket ears |
| None | stirling-annular-screen-stack | screen-stack-48x42x40-50mesh | 1 | optional heat exchanger (with the liner): on the liner's neck |
| None | stirling-slotted-regenerator-liner | liner-2in-slotted-48-40 | 1 | 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 | 1 | the shell |
| None | stirling-clearance-seal-displacer | displacer-cap-40-land | 1 | pressed into the shell; land in the liner bore |
| None | stirling-precision-rods | rod-6x300.25-m6 | 1 | displacer rod: up through the piston's gland and the hollow rod |
| None | hex-nuts-metric | nut-m6 | 2 | lock nuts: displacer cold face, under the displacer yoke |
| None | tri-clamp-spool-bored-honed | spool-2in-3in-bored-48.00 | 1 | power cylinder, on the hot spool |
| None | stirling-clearance-seal-pistons | piston-48-beta-gland | 1 | Ø48.00, gland at the crown |
| None | sleeve-bushings | bushing-6x10x10 | 2 | piston gland, top of the hollow-rod yoke |
| None | stirling-precision-rods | tube-10x7x158.6-m10x1 | 1 | hollow piston rod |
| None | tri-clamp-guide-plate | guide-plate-2in-10mm | 1 | between the power spool and the reducer |
| None | sleeve-bushings | bushing-10x14x15 | 2 | in the guide plate |
| None | sanitary-clamp-reducers | reducer-concentric-3inx2in | 1 | 2 in end down on the guide plate |
| None | sanitary-clamp-tees | tee-3in | 1 | the crankcase: branch down, run along the crankshaft |
| None | tri-clamp-bearing-cap-3in | bearing-cap-3in-608-seal | 1 | +X: bearing and shaft seal, the output side |
| None | tri-clamp-bearing-cap-3in | bearing-cap-3in-608-3x-npt14 | 1 | −X: bearing; fill, gauge and relief ports |
| None | rotary-shaft-seal-8x22x7 | shaft-seal-8x22x7 | 1 | in the +X cap, lip toward the crankcase |
| None | ball-bearings-metric | bearing-608 | 2 | one in each cap |
| None | high-pressure-sanitary-clamps | hp-clamp-2in | 3 | hot–power spool, power spool–plate, plate–reducer; rating above the 7 bar gauge relief setting (not drawn here) |
| None | high-pressure-sanitary-clamps | hp-clamp-3in | 3 | reducer–tee, tee–caps; rating above the 7 bar gauge relief setting (not drawn here) |
| None | tri-clamp-gasket | tc-gasket-2in | 3 | the three 2 in joints |
| None | sanitary-clamp-gaskets | gasket-3in | 3 | the three 3 in joints |
| None | npt-thread-envelopes | npt-1-4-male | 3 | 1/4 NPT stems: crankcase fill, gauge, relief (bodies are the builder's choice) |
| None | stirling-crosshead-yokes | yoke-tube10-m10x1 | 1 | on the hollow rod, stub pin toward −X |
| None | stirling-crosshead-yokes | yoke-rod6-m6 | 1 | on the displacer rod, stub pin toward +X |
| None | dowel-pins-metric | dowel-5x20 | 2 | stub wrist pins |
| None | shaft-collars | collar-5mm | 2 | on the wrist pins |
| None | set-screws-metric | set-m3x4 | 2 | wrist-pin collars |
| None | stirling-conrods-626-625 | conrod-626-625-120 | 1 | piston |
| None | stirling-conrods-626-625 | conrod-626-625-55 | 1 | displacer |
| None | ball-bearings-metric | bearing-626 | 2 | big ends |
| None | ball-bearings-metric | bearing-625 | 2 | small ends |
| None | stirling-built-up-crank-webs | crank-web-56x8-r18 | 1 | −X web, piston pin |
| None | stirling-built-up-crank-webs | link-web-14-r18-r15-90 | 1 | between the con-rods: piston pin and displacer pin |
| None | stirling-built-up-crank-webs | crank-web-56x8-r15 | 1 | +X web, displacer pin |
| None | dowel-pins-metric | dowel-6x30 | 2 | crank pins |
| None | stirling-precision-rods | shaft-8x103.95 | 1 | −X crank stub |
| None | stirling-precision-rods | shaft-8x138.3 | 1 | +X crank stub: through the seal to the flywheel |
| None | shaft-collars | collar-8mm | 2 | inside the bearings: axial location |
| None | set-screws-metric | set-m4x4 | 2 | 8 mm collars |
| None | nut-pocket-flywheels | flywheel-200-m12-b8 | 1 | outside the +X cap |
| None | hex-nut-weights | nut-m12 | 18 | one in each rim pocket |
| None | set-screws-metric | set-m3x6 | 1 | flywheel hub |
| None | spool-hanger-collars | hanger-2in-tab | 2 | on the power spool, bars to the wall |
| None | spool-hanger-collars | hanger-2in-plain | 2 | close the hangers |
| None | socket-head-cap-screws-metric | shcs-m4x20 | 4 | hanger ears |
| None | hex-nuts-metric | nut-m4 | 4 | hanger ears |
| None | socket-head-cap-screws-metric | shcs-m5x25 | 4 | hanger bars through the wall |
| None | hex-nuts-metric | nut-m5 | 4 | hanger bars |

## Where the files are

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

## Build order

1. Frame on the bench; torch stand and shroud on the base.
2. Hot end as on the horizontal gamma: screens, liner pressed in, displacer with its rod.
3. Gasket, clamp, bored power spool; piston (gland bushing in) over the displacer rod into the bore; hollow rod screwed into the piston.
4. Gasket, clamp, guide plate (bushings in) over the hollow rod; gasket, clamp, reducer; hangers on the power spool to the wall.
5. Yokes: hollow-rod yoke (bushing in its top) on the tube, displacer yoke with its lock nut on the rod; wrist pins and collars.
6. Crank: pins and shafts pressed into the webs and the link web with the con-rods and their bearings between; into the tee through a run end, con-rods onto the wrist pins; tee onto the reducer; collars, bearings, caps with gaskets and clamps, seal; flywheel and its nuts.

All printed STLs: https://xemstudio.com/objects/list-tri-clamp-charged-beta/stl-list.txt

## Questions

**How much power?**

In the model at 5 bar gauge: 17–40 W on air at 600 rpm, 36–82 W on helium at 1200 rpm.

**Why helium?**

It carries heat about six times better and flows with less loss, so the same engine runs faster on it.

**Where can it leak?**

At the shaft seal, and through the piston's clearance and the gland only between working space and crankcase (both charged). Keep the fill valve on a regulated supply.

**What are the clamps?**

High-pressure bolted sanitary clamps on every joint, rated above the relief setting.

## Fits with

- [2 in × 152.4 mm closed-end hot spool, bore finished Ø48.00](https://xemstudio.com/objects/tri-clamp-closed-hot-spool-bored/)
- [2 in double-faced guide plate for a hollow Ø10 piston rod](https://xemstudio.com/objects/tri-clamp-guide-plate/)
- [3 in end caps with a bored 608 bearing boss: shaft-seal version and blind version with three 1/4 NPT bosses](https://xemstudio.com/objects/tri-clamp-bearing-cap-3in/)
- [Rotary shaft lip seal 8 × 22 × 7 (envelope)](https://xemstudio.com/objects/rotary-shaft-seal-8x22x7/)
- [Build list: Tri-clamp horizontal gamma generator, 2 in, chargeable](https://xemstudio.com/objects/list-tri-clamp-horizontal-gamma/)
- [Build list: Tri-clamp sealed diaphragm generator, 2 in](https://xemstudio.com/objects/list-tri-clamp-sealed-diaphragm-generator/)