# Ø5 rods with E-clip grooves, 120 and 150 mm

> What size rod with E-clip grooves carries a free-piston Stirling piston or displacer?

- Category: Stirling engines › Free-piston
- Kind: Hardware
- Basis: Ø5 rod; DIN 6799 E-clip groove for Ø5 (Ø4.0 × 0.7), 10 mm from each end
- Page: https://xemstudio.com/objects/e-clip-grooved-rods-5mm/ · JSON: https://xemstudio.com/api/geometry?object=e-clip-grooved-rods-5mm · Plain text: https://xemstudio.com/objects/e-clip-grooved-rods-5mm/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses

**Exact dimensions.** Every file is drawn at true size with no printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part.

## Notes

- 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.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| rod E-clip grooves | Ø4.0 × 0.7 | DIN 6799 E-clip for Ø5 | designed | piston-rod-* |
| rod bores | Ø5 | Ø5 rod | slide | all |
| displacer in the liner | liner bore − 1.0 (0.5 radial) | cylinder liner bore | designed | displacer-* |
| rod E-clip grooves | Ø4.0 × 0.7 | DIN 6799 E-clip for Ø5 | designed | displacer-rod-* |

## Sizes

| 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 |

## Where the files are

- NASA (NTRS, public domain): [Linear alternator design for free-piston Stirling convertors (2005)](https://ntrs.nasa.gov/search?q=20050182934) — PDF — US Government work, public domain
- NASA (NTRS, public domain): [Sunpower/NASA 80 We free-piston Stirling convertor (2002)](https://ntrs.nasa.gov/search?q=20020047256) — PDF — US Government work, public domain
- Wikipedia: [Linear alternator](https://en.wikipedia.org/wiki/Linear_alternator) — web — CC BY-SA 4.0 (text)
- Wikipedia: [Free-piston engine](https://en.wikipedia.org/wiki/Free-piston_engine) — web — CC BY-SA 4.0 (text)
- Long Earth Society: [Engine builds](https://longearthsociety.com/engineering/) — web, video — LES site

## Free STEP/STL (2 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/e-clip-grooved-rods-5mm/index.json

- piston-rod-5x120-grooved: [STEP](https://xemstudio.com/files/hardware/linear-alternator-kit/piston-rod-5x120-grooved.step) · [STL](https://xemstudio.com/files/hardware/linear-alternator-kit/piston-rod-5x120-grooved.stl) — Ø5 × 120 piston rod with two DIN 6799 E-clip grooves Ø4.0 × 0.7, 10 mm from each end (free-piston core version; the tri-clamp kit uses the 5 mm tube)
- displacer-rod-5x150-grooved: [STEP](https://xemstudio.com/files/hardware/free-piston-core/displacer-rod-5x150-grooved.step) · [STL](https://xemstudio.com/files/hardware/free-piston-core/displacer-rod-5x150-grooved.stl) — Ø5 × 150 displacer rod with two DIN 6799 E-clip grooves Ø4.0 × 0.7, 10 mm from each end

## How it fits

### Connects to
- [Free-piston Stirling power piston Ø29.9 × 30 and Ø39.9 × 40](https://xemstudio.com/objects/free-piston-power-piston/): Ø5 rod in the piston's bore
- [Free-piston Stirling displacer Ø29 × 75 and Ø39 × 100](https://xemstudio.com/objects/free-piston-displacer/): Ø5 rod in the displacer's boss
- [Linear alternator mover: Ø35 carrier for 16 Ø10 × 3 magnets](https://xemstudio.com/objects/linear-alternator-mover/): mover clamps the Ø5 rod
- [Gas-spring piston Ø14.9 × 15 and Ø19.9 × 20](https://xemstudio.com/objects/gas-spring-piston/): Ø5 bore on the rod

### Alternatives
- [Crankshafts Ø3, Ø5 and Ø8 with full-length D-flat](https://xemstudio.com/objects/stirling-crankshafts/): other Ø5 rods and tubes

### Also needed
- [Metric shafts Ø3 to Ø10 with D-flats and clip grooves](https://xemstudio.com/objects/metric-shafts/): eclip-5mm in the grooves

## Questions

**What E-clip fits a 5 mm rod?**

DIN 6799 for Ø5: groove Ø4.0 × 0.7, as cut 10 mm from each end of these rods.

**Which rod is the displacer rod?**

The 150 mm one; the 120 mm rod is the power piston rod.

## Fits with

- [Free-piston Stirling displacer Ø29 × 75 and Ø39 × 100](https://xemstudio.com/objects/free-piston-displacer/)
- [Free-piston Stirling power piston Ø29.9 × 30 and Ø39.9 × 40](https://xemstudio.com/objects/free-piston-power-piston/)
- [Linear alternator mover: Ø35 carrier for 16 Ø10 × 3 magnets](https://xemstudio.com/objects/linear-alternator-mover/)
- [Metric shafts Ø3 to Ø10 with D-flats and clip grooves](https://xemstudio.com/objects/metric-shafts/)
- [Crankshafts Ø3, Ø5 and Ø8 with full-length D-flat](https://xemstudio.com/objects/stirling-crankshafts/)