# Con-rods and links with a 626 big end and a 625 small end: 55 to 488 mm

> What con-rod carries the load of a charged 48 mm Stirling piston?

- Category: Hardware › Stirling & thermoacoustic
- Kind: Hardware
- Basis: 626 and 625 sizes from their standards; lengths are design values
- Page: https://xemstudio.com/objects/stirling-conrods-626-625/ · JSON: https://xemstudio.com/api/geometry?object=stirling-conrods-626-625 · Plain text: https://xemstudio.com/objects/stirling-conrods-626-625/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**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

- At 5 bar gauge the piston force swings about ±307 N; a 626 big end on a Ø6 crank pin and a 625 small end on the Ø5 wrist pin carry it on ball bearings.

## 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 |
|---|---|---|---|---|
| big end | Ø19 × 6 pocket, Ø15 lip | 626 bearing OD | press | all |
| small end | Ø16 × 5 pocket, Ø12 lip | 625 bearing OD | press | all |

## Sizes

| length_mm | big end | small end |
|---|---|---|
| 100.0 | 626 | 625 |
| 120.0 | 626 | 625 |
| 55.0 | 626 | 625 |
| 60.0 | 626 | 625 |
| 488.4 | 626 | 625 |

## Where the files are

- Long Earth Society: [Engine builds](https://longearthsociety.com/engineering/) — web, video — LES site

## Free STEP/STL (5 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/stirling-conrods-626-625/index.json

- conrod-626-625-100: [STEP](https://xemstudio.com/files/hardware/stirling-conrods-626-625/conrod-626-625-100.step) · [STL](https://xemstudio.com/files/hardware/stirling-conrods-626-625/conrod-626-625-100.stl) — con-rod 100 between eyes, 7 thick: 626 pocket Ø19 × 6 (big end), 625 pocket Ø16 × 5 (small end)
- conrod-626-625-120: [STEP](https://xemstudio.com/files/hardware/stirling-conrods-626-625/conrod-626-625-120.step) · [STL](https://xemstudio.com/files/hardware/stirling-conrods-626-625/conrod-626-625-120.stl) — con-rod 120 between eyes, 7 thick: 626 pocket Ø19 × 6 (big end), 625 pocket Ø16 × 5 (small end)
- conrod-626-625-55: [STEP](https://xemstudio.com/files/hardware/stirling-conrods-626-625/conrod-626-625-55.step) · [STL](https://xemstudio.com/files/hardware/stirling-conrods-626-625/conrod-626-625-55.stl) — con-rod 55 between eyes, 7 thick: 626 pocket Ø19 × 6 (big end), 625 pocket Ø16 × 5 (small end)
- conrod-626-625-60: [STEP](https://xemstudio.com/files/hardware/stirling-conrods-626-625/conrod-626-625-60.step) · [STL](https://xemstudio.com/files/hardware/stirling-conrods-626-625/conrod-626-625-60.stl) — con-rod 60 between eyes, 7 thick: 626 pocket Ø19 × 6 (big end), 625 pocket Ø16 × 5 (small end)
- conrod-626-625-488.4: [STEP](https://xemstudio.com/files/hardware/stirling-conrods-626-625/conrod-626-625-488.4.step) · [STL](https://xemstudio.com/files/hardware/stirling-conrods-626-625/conrod-626-625-488.4.stl) — con-rod 488.4 between eyes, 7 thick: 626 pocket Ø19 × 6 (big end), 625 pocket Ø16 × 5 (small end)

## Questions

**Which engine uses which?**

100: both rods of the horizontal gamma and the walking-beam gamma's displacer; 120 and 55: the beta's piston and displacer; 60 and the long link: the walking beam's two links.

## Fits with

- [Crosshead yokes with a Ø5 stub wrist pin: Ø6, Ø8 and hollow Ø10 rods](https://xemstudio.com/objects/stirling-crosshead-yokes/)
- [Built-up crank webs for Ø8 shafts and Ø6 crank pins (two-throw cranks at 90°)](https://xemstudio.com/objects/stirling-built-up-crank-webs/)
- [Build list: Tri-clamp horizontal gamma generator, 2 in, chargeable](https://xemstudio.com/objects/list-tri-clamp-horizontal-gamma/)
- [Build list: Tri-clamp charged beta, 2 in](https://xemstudio.com/objects/list-tri-clamp-charged-beta/)