Rhombic drive link, 30 mm centres — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/rhombic-link/  (CC BY 4.0)
Basis: Rhombic kinematics (tools/rhombic_geom.py): four equal links L = 30 between crank pins at e = 7 on gears 66 apart and yoke pivots at ±12.7
Catalog version: 2026-10-20

Sizes: see table below
- Four identical links join the two crank pins to the two yokes, forming the rhombus. Each is 30 mm between Ø3 holes (fit: run), 38 × 8 × 5 with round ends.
- Two ride each crank pin: the lower link next to the gear, the upper link outside it.
- Link length, gear centres, throw and yoke span together set the phase: here 90.0° with both strokes 20.12 mm.

parameter  value
centres  30.0
outline  38 × 8 × 5
holes  2 × Ø3 (run)
quantity  4

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Wikipedia: Rhombic drive — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Rhombic_drive
- Wikipedia: Stirling engine — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Stirling_engine
- Philips Research / Meijer: The Philips Stirling engine (rhombic drive papers, 1958–1965) — web — reference [verify license at link] — https://en.wikipedia.org/wiki/Rhombic_drive#History
- 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/rhombic-link/index.json
API: https://xemstudio.com/api/geometry?object=rhombic-link