# Frame for the rolling-diaphragm tri-clamp engines: base, wall, hanger and torch-stand mount

> What frame holds a 2 in tri-clamp engine over a torch?

- Category: Hardware › Stirling & thermoacoustic
- Kind: Hardware
- Basis: Design values; hanger bar hole spacing (78.8) and height from the spool hanger collars on this site; torch-stand hole pattern from the torch stand on this site
- Page: https://xemstudio.com/objects/tri-clamp-rd-engine-frame/ · JSON: https://xemstudio.com/api/geometry?object=tri-clamp-rd-engine-frame · Plain text: https://xemstudio.com/objects/tri-clamp-rd-engine-frame/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.** Every file is drawn at true size with no printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part.

## Notes

- One frame for all three rolling-diaphragm engines: the 2 in cup hangs from a spool hanger bolted to the wall, its closed end 40 mm over the torch stand's ring.
- The wall has a window behind the hot end and the optional finned cooler, so the fins clear it and the flame has air.
- The base reaches 300 mm toward +X, under the power head and flywheel on the tee's branch.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| hanger-bar holes | 2 × Ø5.5 | M5 screws | designed | all |
| torch-stand holes | 2 × Ø3.3 | M4 tap drill | designed | all |

## Sizes

| feature | value_mm |
|---|---|
| base | 370 × 150 × 8 |
| wall | 124 × 10, top z 234.85 |
| hanger holes | x ±39.4, z 226.85 |
| torch stand holes | (±25, 28), M4 |
| cup bottom | 93.0 |

## Where the files are

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

## Free STEP/STL (1 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/tri-clamp-rd-engine-frame/index.json

- rd-frame-2in: [STEP](https://xemstudio.com/files/hardware/tri-clamp-rd-engine-frame/rd-frame-2in.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-rd-engine-frame/rd-frame-2in.stl) — frame: base 370 × 150 × 8 (x −70..300, y −95..55), wall x ±62, y -49.4..-39.4 to z 234.85 with a window x ±30 from z 93 to 217.85, 2 × Ø5.5 at x ±39.4, z 226.85 for the hanger bar, two gussets, 2 × M4 tapped (Ø3.3) at (±25, 28) for the torch stand

## Questions

**Which engines use it?**

The rolling-diaphragm beta, Ringbom and gamma: they share the cup, the hanger height and the torch position.

## Fits with

- [Spool hanger collars: clamp a tri-clamp spool to 2020 extrusion over the flame (1.5, 2, 3 in)](https://xemstudio.com/objects/spool-hanger-collars/)
- [Torch stand for a horizontal tri-clamp hot leg](https://xemstudio.com/objects/tri-clamp-torch-stand/)
- [Build list: Tri-clamp rolling-diaphragm beta, 2 in](https://xemstudio.com/objects/list-tri-clamp-rd-beta/)
- [Build list: Tri-clamp rolling-diaphragm Ringbom, 2 in](https://xemstudio.com/objects/list-tri-clamp-rd-ringbom/)
- [Build list: Tri-clamp rolling-diaphragm gamma, 2 in](https://xemstudio.com/objects/list-tri-clamp-rd-gamma/)