# Build list: Tri-clamp elbow diaphragm alpha, 2 in

> What parts do I need to build a Tri-clamp elbow diaphragm alpha, 2 in?

- Category: Stirling engines › Guide
- 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-elbow-diaphragm-alpha/ · JSON: https://xemstudio.com/api/geometry?object=list-tri-clamp-elbow-diaphragm-alpha · Plain text: https://xemstudio.com/objects/list-tri-clamp-elbow-diaphragm-alpha/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses

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

## Notes

- A torch-heated alpha in 2 in tri-clamp: a square of fittings with a diaphragm head on each tee branch and both rods on one crank pin at 90°.
- Numbers: 2 in · two diaphragms at 15 mm stroke, 14.2 mL each, 90° on one pin · dead volume 478 mL with the fillers (1228 without) · swept / dead 0.030

## Sizes

| subsystem | object | parts | qty | note |
|---|---|---|---|---|
| None | tri-clamp-diaphragm-alpha-frame | alpha-frame-2in | 1 | base, two feet, diagonal strut, bearing block |
| None | tri-clamp-torch-stand | torch-stand-40 | 1 | under the middle of the hot spool; the heat source is a torch flame |
| None | socket-head-cap-screws-metric | shcs-m4x20 | 2 | torch stand to the frame |
| None | sanitary-clamp-elbows | elbow-90-2in | 1 | the corner: hot leg to cold leg |
| None | sanitary-clamp-spools | spool-2in-3in | 2 | hot leg (over the flame) and cold leg (cooler) |
| None | sanitary-clamp-tees | tee-short-2in | 2 | hot tee (branch up) and cold tee (branch inward) |
| None | tri-clamp-end-cap | tc-cap-2in-flat | 2 | close the tees' runs |
| None | tri-clamp-hot-gasket | hot-gasket-2in | 2 | both hot-spool joints |
| None | tri-clamp-heat-shield | heat-shield-2in | 2 | on the hot spool, flame side of each clamp |
| None | tri-clamp-gasket | tc-gasket-2in | 4 | cap joints, elbow–cold spool, cold spool–cold tee |
| None | tri-clamp-clamps | clamp-half-2in | 16 | eight joints, two halves each |
| None | socket-head-cap-screws-metric | shcs-m5x30 | 16 | clamp bolts |
| None | hex-nuts-metric | nut-m5 | 16 | clamp nuts, in the hex traps |
| None | regenerator-cage | regenerator-cage-47-5x40 | 1 | in the cold spool at the elbow joint, on the gasket lip |
| None | regenerator-mesh-disc | mesh-disc-44mm | 80 | fill the cage, 40 mm |
| None | tri-clamp-volume-filler | plug-tee-2in-blind | 2 | fill both tee runs; passage from the spool side to the branch |
| None | tri-clamp-volume-filler | sleeve-2in-76.2 | 1 | hot spool: 1 mm heater gap |
| None | tri-clamp-volume-filler | sleeve-2in-32 | 1 | cold spool above the regenerator: 1 mm cooler gap |
| None | tri-clamp-finned-cooler | cooler-half-2in-56 | 2 | on the cold spool; or the jacket shell |
| None | socket-head-cap-screws-metric | shcs-m4x30 | 4 | cooler (or jacket) ears |
| None | hex-nuts-metric | nut-m4 | 6 | cooler (or jacket) ears (4), torch stand (2) |
| None | tri-clamp-jacket-shell | jacket-half-2in-56 | 2 | optional, in place of the finned cooler |
| None | tri-clamp-jacket-shell | jacket-port-cap | 2 | optional, one per jacket half |
| None | tri-clamp-diaphragm-head | diaphragm-head-2in | 2 | hot (up) and cold (inward) |
| None | tri-clamp-diaphragm-membrane | membrane-2in | 2 | clamped in place of the gaskets |
| None | tri-clamp-diaphragm-disc | diaphragm-disc-2in | 2 | head side of each membrane, carries the rod |
| None | tri-clamp-diaphragm-disc | diaphragm-backing-2in | 2 | gas side of each membrane |
| None | socket-head-cap-screws-metric | shcs-m2x8 | 6 | three per membrane |
| None | hex-nuts-metric | nut-m2 | 6 | three per membrane |
| None | displacer-rods | rod-3x150 | 2 | diaphragm rods |
| None | rod-clevises | rod-clevis-3mm | 2 | one per rod |
| None | connecting-rods-623 | conrod-50 | 2 | both on the one crank pin |
| None | ball-bearings-metric | bearing-623 | 4 | con-rod eyes |
| None | dowel-pins-metric | dowel-3x20 | 2 | clevis pins: each con-rod sits beside its clevis on the pin |
| None | dowel-pins-metric | dowel-3x30 | 1 | crank pin |
| None | counterweighted-crank-discs | cw-crank-disc-stroke15 | 1 | 15 stroke, one pin |
| None | stirling-crankshafts | crankshaft-5x80-dflat | 1 |  |
| None | ball-bearings-metric | bearing-625 | 2 | in the strut's bearing block |
| None | shaft-collars | collar-5mm | 2 | either side of the bearing block |
| None | nut-pocket-flywheels | flywheel-150-m10-b5 | 1 | behind the bearing block |
| None | hex-nut-weights | nut-m10 | 18 | one in each rim pocket |
| None | set-screws-metric | set-m3x4 | 8 | grubs: 2 diaphragm discs, 2 clevises, crank disc, 2 collars, flywheel |
| None | set-screws-metric | set-m4x10 | 3 | centre the torch head in the stand ring |

## 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 on the frame.
2. Elbow on its foot. Cold side: Type B gasket, regenerator cage with its mesh on the lip inside the cold spool, sleeve above it, clamp; cooler halves on the spool; Type B gasket, cold tee (branch toward the crank), tee plug from the spool end, Type B gasket, cap, clamps.
3. Hot side: hot gasket, hot spool with its sleeve, hot gasket, hot tee (branch up) with its plug, Type B gasket, cap, clamps; heat shields on the spool next to both hot clamps.
4. Diaphragms: backing disc, membrane, centre disc and three M2 × 8 each; Ø3 × 150 rod in each boss; membrane on the branch, head over the rod, clamp.
5. Crankshaft through the bearing block with collars, flywheel with its nuts, crank disc with the Ø3 × 30 pin; each con-rod beside its rod clevis on a Ø3 × 20 pin; both big ends on the one crank pin.

All printed STLs: https://xemstudio.com/objects/list-tri-clamp-elbow-diaphragm-alpha/stl-list.txt

## Questions

**What parts do I need for the tri-clamp elbow diaphragm alpha?**

43 parts, every one a free STEP/STL on this site; see the table and the build order on this page.

**How does one crank pin give 90°?**

The hot rod is vertical and the cold rod horizontal, and both lines pass through the crank axis, so the two strokes are a quarter turn apart.

**How far is the hot diaphragm from the flame?**

About 144 mm from the flame's contact point on the hot spool to the centre of the hot membrane, with the clamped hot-tee joint and the tee between them.

## Fits with

- [Tri-clamp diaphragm head: 1.5 and 2 in, membrane in place of the gasket](https://xemstudio.com/objects/tri-clamp-diaphragm-head/)
- [Tri-clamp diaphragm membrane: flat, 1.5 and 2 in clamped size](https://xemstudio.com/objects/tri-clamp-diaphragm-membrane/)
- [Tri-clamp diaphragm centre disc and backing disc: 1.5 and 2 in](https://xemstudio.com/objects/tri-clamp-diaphragm-disc/)
- [Tri-clamp volume fillers: 2 in tee-run plugs and annular sleeves](https://xemstudio.com/objects/tri-clamp-volume-filler/)
- [Tri-clamp finned cooler: clamp-on halves for a 2 in tube](https://xemstudio.com/objects/tri-clamp-finned-cooler/)
- [Tri-clamp jacket shell: clamp-on sealed jacket for a 2 in tube](https://xemstudio.com/objects/tri-clamp-jacket-shell/)
- [Torch stand for a horizontal tri-clamp hot leg](https://xemstudio.com/objects/tri-clamp-torch-stand/)
- [Frame for the 2 in tri-clamp elbow diaphragm alpha](https://xemstudio.com/objects/tri-clamp-diaphragm-alpha-frame/)
- [Sanitary clamp elbows, 90° and 45°, ½ to 4 in (tri-clamp style, BPE)](https://xemstudio.com/objects/sanitary-clamp-elbows/)
- [Sanitary clamp tees and short-outlet tees (7MP, 7MPS): ½ to 4 in](https://xemstudio.com/objects/sanitary-clamp-tees/)