# Burner shroud for a 2 in tri-clamp hot end

> How do I keep a torch or burner flame on the hot end of a Stirling engine?

- Category: Hardware › Stirling & thermoacoustic
- Kind: Hardware
- Basis: Design values from the sealed generator layout: shell 4 mm clear of the optional fin sleeve's Ø80 fins, open bottom over the torch stand, exhaust windows under the lid; ISO 273 medium clearance (Ø4.5) for the M4 foot screws
- Page: https://xemstudio.com/objects/tri-clamp-burner-shroud/ · JSON: https://xemstudio.com/api/geometry?object=tri-clamp-burner-shroud · Plain text: https://xemstudio.com/objects/tri-clamp-burner-shroud/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

- A Ø92 / Ø88 shell round the hot end (the cup's closed end, with or without the fin sleeve), from 15 mm below the cup's bottom to 10 mm above the sleeve's top fin. The bottom is open: the torch or burner below fires up into it. A lid closes the top down to Ø54.8, 2 mm clear of the tube, and six 14 × 10 windows under the lid let the gas out sideways once it has passed the fins.
- Three 8 × 8 legs stand it on the frame base; each leg's 20 × 12 × 4 foot runs outward and takes an M4 × 10 into a tapped hole in the base, clear of the leg. The shroud touches nothing else: not the head, not the fins, not the torch stand.
- The 4 mm annulus between the sleeve's fins and the shell keeps the flame gas against the fins (without the sleeve, against the bare tube). The heat source is the builder's choice: a propane or butane torch head in the torch stand, or a natural-gas or biogas burner that fires into the open bottom.

## 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 |
|---|---|---|---|---|
| shell bore | Ø88 | fin sleeve fins Ø80 (no contact) | designed | all |
| lid opening | Ø54.8 | cup tube Ø50.8 (no contact) | designed | all |
| foot holes | 3 × Ø4.5 | M4 clearance (ISO 273 medium) | designed | all |

## Sizes

| feature | value |
|---|---|
| shell | Ø92 / Ø88 |
| above the base | 70 to 138.5 |
| lid opening | Ø54.8 |
| exhaust | 6 × 14 × 10 under the lid |
| legs | 3 × 8 × 8 on r 49, feet 20 × 12 × 4, Ø4.5 at r 59 |
| gap to the fins | 4.0 |

## Where the files are

- ISO: [ISO 273 clearance holes for bolts and screws (fine / medium / coarse)](https://www.iso.org/standard/4196.html) — standard — dimensions are facts (verify at link)
- 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-burner-shroud/index.json

- burner-shroud-2in: [STEP](https://xemstudio.com/files/hardware/tri-clamp-burner-shroud/burner-shroud-2in.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-burner-shroud/burner-shroud-2in.stl) — burner shroud: shell Ø92 / Ø88 from 70 to 138.5 above its feet, lid to Ø54.8, 6 windows 14 × 10 under the lid, 3 legs 8 × 8 on r 49 with 20 × 12 × 4 feet out to r 65, Ø4.5 holes at r 59

## Questions

**Does the shroud touch the hot end?**

No: 4 mm clear of the fin sleeve radially and 2 mm clear of the tube at the lid. It stands on its own feet.

**Which heat sources fit?**

Anything that fires up into the Ø88 open bottom: a torch head held in the torch stand, or a small gas burner.

## Fits with

- [Hot-end fin sleeve for a 2 in tri-clamp cup: slide-on ring fins, set-screw held](https://xemstudio.com/objects/tri-clamp-hot-fin-sleeve/)
- [Tri-clamp cups: closed-end spools (ferrule on a capped tube), 1.5, 2 and 3 in](https://xemstudio.com/objects/tri-clamp-cups/)
- [Torch stand for a horizontal tri-clamp hot leg](https://xemstudio.com/objects/tri-clamp-torch-stand/)
- [Frame for the 2 in tri-clamp sealed diaphragm generator](https://xemstudio.com/objects/tri-clamp-sealed-generator-frame/)
- [Build list: Tri-clamp sealed diaphragm generator, 2 in](https://xemstudio.com/objects/list-tri-clamp-sealed-diaphragm-generator/)