Alpha V-twin crank disc Ø26, one pin, 16 mm stroke — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/alpha-v-twin-crank-disc/  (CC BY 4.0)
Basis: 90° V alpha: both con-rods on one pin; throw 8 (stroke 16)
Catalog version: 2026-10-20

Sizes: see table below
- Ø26 × 6 disc with a Ø5 bore (fit: slide) and a Ø2.5 radial hole (M3 tap size) for the grub screw.
- ONE Ø3 hole (fit: press) at 8 mm for a Ø3 × 20 crank pin; both con-rods ride it, one plane each, with 1 mm spacers and a 3 mm collar on the end.
- A two-pin disc with pins 90° apart under a 90° V would give 0° or 180° and the engine would not run; that disc is for parallel cylinders.

parameter  value
disc  Ø26 × 6
bore  Ø5
throw  8
stroke  16
pin hole  1 × Ø3
grub hole  Ø2.5

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/
- Wikipedia: Stirling engine (alpha configuration) — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Stirling_engine

Free files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/alpha-v-twin-crank-disc/index.json
API: https://xemstudio.com/api/geometry?object=alpha-v-twin-crank-disc