# Ross yoke crank disc Ø24, 6 mm throw

> What crank disc drives a Ross yoke?

- Category: Stirling engines › Drives & mechanisms
- Kind: Hardware
- Basis: Solved Ross linkage: crank throw e = 6
- Page: https://xemstudio.com/objects/ross-crank-disc/ · JSON: https://xemstudio.com/api/geometry?object=ross-crank-disc · Plain text: https://xemstudio.com/objects/ross-crank-disc/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

- The crank that drives the Ross yoke: Ø24 × 6, Ø5 bore (fit: slide) for the crankshaft, Ø2.5 radial hole (M3 tap size) for the grub screw.
- One Ø3 hole (fit: press) at 6 mm takes a Ø3 × 20 crank pin; the yoke's bottom vertex rides on it, and a 3 mm collar holds it on.

## 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 |
|---|---|---|---|---|
| crank-disc bore | Ø5 | Ø5 crankshaft (M3 grub) | slide | ross-crank-disc-* |
| crank-disc pin hole | Ø3 | Ø3 crank pin | press | ross-crank-disc-* |

## Sizes

| parameter | value |
|---|---|
| disc | Ø24 × 6 |
| bore | Ø5 |
| throw | 6 |
| pin hole | Ø3 |
| grub hole | Ø2.5 |

## Where the files are

- Wikipedia: [Ross yoke](https://en.wikipedia.org/wiki/Ross_yoke) — web — CC BY-SA 4.0 (text)
- Long Earth Society: [Engine builds](https://longearthsociety.com/engineering/) — web, video — LES site

## Free STEP/STL (1 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/ross-crank-disc/index.json

- ross-crank-disc-e6: [STEP](https://xemstudio.com/files/hardware/ross-yoke-kit/ross-crank-disc-e6.step) · [STL](https://xemstudio.com/files/hardware/ross-yoke-kit/ross-crank-disc-e6.stl) — crank disc Ø24 × 6, Ø5 bore, Ø2.5 tap-drill hole for an M3 grub, Ø3 pin at 6 mm (the yoke rides on it)

## How it fits

### Goes in or on
- [Ross yoke alpha frame for two 10 mL syringes](https://xemstudio.com/objects/ross-yoke-frame/): on the shaft beside the boss

### Connects to
- [Ross yoke a = h = 20 for two parallel syringes](https://xemstudio.com/objects/ross-yoke/): yoke's bottom vertex on the Ø3 pin
- [Crankshafts Ø3, Ø5 and Ø8 with full-length D-flat](https://xemstudio.com/objects/stirling-crankshafts/): Ø5 × 80 crankshaft, Ø3 × 20 pin

### Also needed
- [Set screws (grub screws), M3–M8 (ISO 4026)](https://xemstudio.com/objects/set-screws-metric/): M3 grub

## Questions

**What throw does the Ross yoke crank have?**

6 mm; with a = h = 20 it gives piston strokes of 17.0 and 17.2 mm.

**How is the Ross crank disc fixed to the shaft?**

An M3 grub in the Ø2.5 radial hole onto the Ø5 shaft's D-flat.

## Fits with

- [Ross yoke a = h = 20 for two parallel syringes](https://xemstudio.com/objects/ross-yoke/)
- [Ross yoke alpha frame for two 10 mL syringes](https://xemstudio.com/objects/ross-yoke-frame/)
- [Crankshafts Ø3, Ø5 and Ø8 with full-length D-flat](https://xemstudio.com/objects/stirling-crankshafts/)
- [Build list: Ross yoke alpha, two parallel 10 mL syringes](https://xemstudio.com/objects/list-ross-yoke-alpha/)