Ø5 rods with E-clip grooves, 120 and 150 mm — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/e-clip-grooved-rods-5mm/  (CC BY 4.0)
Basis: Ø5 rod; DIN 6799 E-clip groove for Ø5 (Ø4.0 × 0.7), 10 mm from each end
Catalog version: 2026-10-20

Sizes: see table below
- Plain Ø5 rods with two DIN 6799 E-clip grooves, Ø4.0 × 0.7 wide, 10 mm from each end; 0.5 mm chamfer on one end.
- Piston-rod-5x120-grooved (Ø5 × 120) carries the free-piston core's power piston and the linear alternator mover; displacer-rod-5x150-grooved (Ø5 × 150) carries the displacer.
- The parts on them have Ø5 bores (fit: slide); E-clips in the grooves locate them.

file  diameter  length  grooves  groove from ends
piston-rod-5x120-grooved  5  120  2 × Ø4.0 × 0.7  10
displacer-rod-5x150-grooved  5  150  2 × Ø4.0 × 0.7  10

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- NASA (NTRS, public domain): Linear alternator design for free-piston Stirling convertors (2005) — PDF — US Government work, public domain — https://ntrs.nasa.gov/search?q=20050182934
- NASA (NTRS, public domain): Sunpower/NASA 80 We free-piston Stirling convertor (2002) — PDF — US Government work, public domain — https://ntrs.nasa.gov/search?q=20020047256
- Wikipedia: Linear alternator — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Linear_alternator
- Wikipedia: Free-piston engine — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Free-piston_engine
- Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 2 parts): https://xemstudio.com/files/hardware/e-clip-grooved-rods-5mm/index.json
API: https://xemstudio.com/api/geometry?object=e-clip-grooved-rods-5mm