Eccentric sheaves Ø30 at 3, 5 and 8 mm offset — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/eccentric-sheaves/  (CC BY 4.0)
Basis: Disc on a shaft offset e from its centre; stroke = 2e
Catalog version: 2026-10-20

Sizes: see table below
- A Ø30 × 8 disc with a Ø5 shaft hole offset 3, 5 or 8 mm from its centre: 6, 10 or 16 mm stroke.
- A radial Ø2.5 hole (M3 tap drill) at mid-thickness locks it to the shaft.
- It turns inside the Ø30 strap, which carries the load round its whole bore; it sits anywhere along a straight shaft without a crank throw.

file  offset e  stroke  disc  shaft
eccentric-d30-e3  3  6  Ø30 × 8  5
eccentric-d30-e5  5  10  Ø30 × 8  5
eccentric-d30-e8  8  16  Ø30 × 8  5

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Wikipedia: Eccentric (mechanism) — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Eccentric_(mechanism)
- Long Earth Society: Engine and rig builds on extrusion frames — web, video — LES site — https://longearthsociety.com/engineering/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 3 parts): https://xemstudio.com/files/hardware/eccentric-sheaves/index.json
API: https://xemstudio.com/api/geometry?object=eccentric-sheaves