Shaft adapter Ø5 to Ø8 × 20 — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/shaft-adapter-5-to-8mm/  (CC BY 4.0)
Basis: Sleeve with a Ø5 bore and Ø8 OD, two M3 radial holes
Catalog version: 2026-10-20

Sizes: see table below
- A sleeve Ø8 OD × Ø5 bore × 20 long.
- Two Ø2.5 radial holes (M3 tap drill) through both walls, 5 mm from each end: one grub bears on the Ø5 shaft's flat, the other lines up under the flywheel's set screw.
- It puts any Ø8-bore hub (the Ø80–Ø150 spoked flywheels) on a Ø5 crankshaft.

feature  value_mm
OD  8
bore  5
length  20
grub holes  2 × Ø2.5 at 5 and 15

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Long Earth Society: Tri-clamp Stirling 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/shaft-adapter-5-to-8mm/index.json
API: https://xemstudio.com/api/geometry?object=shaft-adapter-5-to-8mm