# Thermoacoustic fin sleeve: clamp-on, 2 in tube, 34 mm (optional)

> How do I get more of a torch's heat into a 2 inch tube?

- Category: Stirling engines › Thermoacoustic & fluidyne
- Kind: Hardware
- Basis: Bore = 2 in tube OD Ø50.8; length covers the 12 mm hot exchanger with 11 mm each side
- Page: https://xemstudio.com/objects/thermoacoustic-fin-sleeve/ · JSON: https://xemstudio.com/api/geometry?object=thermoacoustic-fin-sleeve · Plain text: https://xemstudio.com/objects/thermoacoustic-fin-sleeve/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

- Two halves with 24 radial fins each side of the split, clamped round the plain core tube over the hot exchanger with one M4 × 16 and nut each side. The flame gas in the burner drum passes between the fins; the fins conduct into the tube wall, the wall into the slotted hot exchanger inside.
- Optional: the engine is complete without it (the drum then heats the bare tube); with it the tube wall reaches a given temperature with less flame.
- Fits: bore clamps the tube (1 mm split take-up); ear holes M4 clearance.

## 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 |
|---|---|---|---|---|
| bore | Ø50.8 | 2 in tube outside over the hot exchanger | clamp | all |
| split | 1.0 total (0.5 per half) | the other half | clamp | all |
| ear holes | Ø4.5 | M4 clearance (ISO 273 medium) | designed | all |
| fins | 24 × 1.5 to Ø72 | flame gas (no contact) | designed | all |

## Sizes

| feature | value |
|---|---|
| bore | Ø50.8 |
| fins | 24 × 1.5 to Ø72 |
| length | 34 |

## Where the files are

- Xem Studio: [tools/gen_ta_power.py: the network model and every dimension on this page](https://xemstudio.com/) — code — CC BY 4.0
- 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/thermoacoustic-fin-sleeve/index.json

- fin-sleeve-half-2in-34: [STEP](https://xemstudio.com/files/hardware/thermoacoustic-fin-sleeve/fin-sleeve-half-2in-34.step) · [STL](https://xemstudio.com/files/hardware/thermoacoustic-fin-sleeve/fin-sleeve-half-2in-34.stl) — fin-sleeve half (y ≥ 0.5): bore Ø50.8, wall 3, 24 radial fins 1.5 thick to Ø72, 34 long; ears x ±27.9..44 with Ø4.5 at x ±40

## Questions

**Why not weld fins on the spool?**

A clamp-on sleeve keeps the spool a plain, orderable part and can be left off.

## Fits with

- [Thermoacoustic burner drum: one torch heats one or three vertical 2 in tubes](https://xemstudio.com/objects/thermoacoustic-burner-drum/)
- [Thermoacoustic slotted exchanger insert: 2 in bore, 14 and 12 mm](https://xemstudio.com/objects/thermoacoustic-slotted-exchanger-insert/)
- [Build list: Thermoacoustic-Stirling ring generator, three 2 in units, pressurised](https://xemstudio.com/objects/list-ta-ring-3x2in/)