Connecting rods 30 to 80 mm centres with 623 pockets — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/connecting-rods-623/  (CC BY 4.0)
Basis: Flat rod 5 thick, Ø14 ends with Ø10 pockets (623 OD) at the stated centres
Catalog version: 2026-10-20

Sizes: see table below
- A flat rod 5 thick: an 8 mm wide web between two Ø14 bosses, each with a Ø10 pocket through for a 623 (3 × 10 × 4).
- Centres 30, 40, 50, 60 and 80 mm; overall length centres + 14.
- Both ends run on Ø3 pins. A rod at least twice the stroke keeps the piston side load low; the 2 in engines pair conrod-50 with a 20 mm stroke.

file  centres  overall  thickness  pockets
conrod-30  30  44  5  2 × Ø10
conrod-40  40  54  5  2 × Ø10
conrod-50  50  64  5  2 × Ø10
conrod-60  60  74  5  2 × Ø10
conrod-80  80  94  5  2 × Ø10

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Wikipedia: Crank (mechanism) — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Crank_(mechanism)
- Wikipedia: Flywheel — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Flywheel
- Wikipedia: Stirling engine — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Stirling_engine
- Long Earth Society: Engine builds that use these parts (videos and write-ups) — web, video — LES site — https://longearthsociety.com/engineering/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 5 parts): https://xemstudio.com/files/hardware/connecting-rods-623/index.json
API: https://xemstudio.com/api/geometry?object=connecting-rods-623