Thermoacoustic fin sleeve for the flame-shroud band: 2 in tube, 34 mm, fins to Ø72, ears inside Ø73 — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/thermoacoustic-shroud-fin-sleeve/  (CC BY 4.0)
Basis: Design values: the band of ta-shroud-2in-front / -back is Ø75 inside (r 37.5) and 35 between its end walls; the sleeve, its ears, M4 heads and nuts stay inside r 37
Catalog version: 2026-10-20

Sizes: see table below
- Two halves clamped round a plain 2 in tube over a hot exchanger, inside the flame shroud's band: the flame gas from the flue passes between the fins, the fins conduct into the tube wall and the wall into the exchanger inside.
- Everything stays inside the band: fins to r 36, ears to r 36, the M4 × 12 head and nut at x ±32 inside r 37; 34 long in the band's 35. No fin within ±20° of the ears, so the screw head and nut have room.
- Optional: the engine runs without it (the flame heats the bare tube). Fits: bore clamps the tube (1 mm split take-up); ear holes M4 clearance.

part  bore_mm  length_mm  fins  fin_tip_dia_mm  ears_to_r_mm  screws
ta-fin-sleeve-half-2in-34-r36  50.8  34.0  20 per sleeve, 1.5 thick  72.0  36.0  2 × M4 × 12 + nuts

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Xem Studio: tools/gen_ta_modular.py: the section geometry, the network model and every number on these pages — code — CC BY 4.0 — https://xemstudio.com/
- Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/thermoacoustic-shroud-fin-sleeve/index.json
API: https://xemstudio.com/api/geometry?object=thermoacoustic-shroud-fin-sleeve