Ground rods, hollow piston rod and crank shafts for the performance engines (Ø6, Ø8, Ø10 / 7) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/stirling-precision-rods/  (CC BY 4.0)
Basis: Design values; lengths from the engines' layouts
Catalog version: 2026-10-20

Sizes: see table below
- Ground rods cut to length with threaded ends (threads drawn at the major diameter): the displacer rods (Ø6, M6), the gamma's piston rod (Ø8, M8), the beta's hollow piston rod (Ø10 / Ø7, M10 × 1; the displacer rod runs inside it) and the Ø8 crank shafts the built-up cranks are pressed onto.

part  size
rod-6x423.2-m6  Ø6 × 423.20
rod-8x304.85-m8  Ø8 × 304.85
rod-6x300.25-m6  Ø6 × 300.25
tube-10x7x158.6-m10x1  Ø10/7 × 158.60
shaft-8x56.5  Ø8 × 56.50
shaft-8x88  Ø8 × 88.00
shaft-8x46.3  Ø8 × 46.30
shaft-8x103.95  Ø8 × 103.95
shaft-8x138.3  Ø8 × 138.30

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/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 13 parts): https://xemstudio.com/files/hardware/stirling-precision-rods/index.json
API: https://xemstudio.com/api/geometry?object=stirling-precision-rods