# Swash (wobble) plates Ø40 at 10, 15 and 20°

> How much stroke does a swash plate give?

- Category: Stirling engines › Drives & mechanisms
- Kind: Hardware
- Basis: A follower at radius r on a plate tilted θ moves 2 r sin θ per turn; Ø40 × 4 plate on a Ø13 × 20 hub
- Page: https://xemstudio.com/objects/swash-plate-40mm/ · JSON: https://xemstudio.com/api/geometry?object=swash-plate-40mm · Plain text: https://xemstudio.com/objects/swash-plate-40mm/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

- A Ø40 × 4 plate set at 10, 15 or 20° on a Ø13 × 20 hub with a Ø5 bore; a radial Ø2.5 hole (M3 tap drill) 6 mm from the hub's mid-length locks it.
- Stroke = 2 × r × sin θ. At the rim (r 20): 6.9, 10.4, 13.7 mm; at r 18: 6.3, 9.3, 12.3 mm.
- Followers spaced round one plate drive several cylinders from one shaft; each peaks at a shaft angle set by its position.

## 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 |
|---|---|---|---|---|
| hub bore | Ø5 | Ø5 shaft | slide | swash-plate-* |
| set-screw hole | Ø2.5 | M3 tap drill | designed | swash-plate-* |

## Sizes

| file | tilt | stroke r 20 | stroke r 18 | hub | bore |
|---|---|---|---|---|---|
| swash-plate-40-10deg | 10° | 6.9 | 6.3 | Ø13 × 20 | 5 |
| swash-plate-40-15deg | 15° | 10.4 | 9.3 | Ø13 × 20 | 5 |
| swash-plate-40-20deg | 20° | 13.7 | 12.3 | Ø13 × 20 | 5 |

## Where the files are

- Wikipedia: [Swashplate](https://en.wikipedia.org/wiki/Swashplate) — web — CC BY-SA 4.0 (text)
- Long Earth Society: [Engine and rig builds on extrusion frames](https://longearthsociety.com/engineering/) — web, video — LES site

## Free STEP/STL (3 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/swash-plate-40mm/index.json

- swash-plate-40-10deg: [STEP](https://xemstudio.com/files/hardware/swash-plate/swash-plate-40-10deg.step) · [STL](https://xemstudio.com/files/hardware/swash-plate/swash-plate-40-10deg.stl) — swash (wobble) plate Ø40, 10° tilt, 6.9 mm stroke at the rim, Ø5 shaft, Ø2.5 set-screw hole
- swash-plate-40-15deg: [STEP](https://xemstudio.com/files/hardware/swash-plate/swash-plate-40-15deg.step) · [STL](https://xemstudio.com/files/hardware/swash-plate/swash-plate-40-15deg.stl) — swash (wobble) plate Ø40, 15° tilt, 10.4 mm stroke at the rim, Ø5 shaft, Ø2.5 set-screw hole
- swash-plate-40-20deg: [STEP](https://xemstudio.com/files/hardware/swash-plate/swash-plate-40-20deg.step) · [STL](https://xemstudio.com/files/hardware/swash-plate/swash-plate-40-20deg.stl) — swash (wobble) plate Ø40, 20° tilt, 13.7 mm stroke at the rim, Ø5 shaft, Ø2.5 set-screw hole

## How it fits

### Goes in or on
- [Metric shafts Ø3 to Ø10 with D-flats and clip grooves](https://xemstudio.com/objects/metric-shafts/): Ø5 shaft, M3 grub

### Connects to
- [Swash plate follower 8 × 8 × 30 with Ø8 ball end](https://xemstudio.com/objects/swash-follower/): Ø8 ball on the plate face

### Alternatives
- [Eccentric sheaves Ø30 at 3, 5 and 8 mm offset](https://xemstudio.com/objects/eccentric-sheaves/): single strap drive

### Also needed
- [Set-screw shaft collars Ø3 to Ø12](https://xemstudio.com/objects/shaft-collars/): locates the plate

## Questions

**How much stroke does a swash plate give?**

2 × r × sin θ: the Ø40 plate at 15° gives 9.3 mm to a follower at r 18.

**Can one plate drive more than one cylinder?**

Yes: followers spaced round the plate each reach top of stroke at a different shaft angle.

## Fits with

- [Swash plate follower 8 × 8 × 30 with Ø8 ball end](https://xemstudio.com/objects/swash-follower/)
- [Metric shafts Ø3 to Ø10 with D-flats and clip grooves](https://xemstudio.com/objects/metric-shafts/)
- [Set-screw shaft collars Ø3 to Ø12](https://xemstudio.com/objects/shaft-collars/)
- [Eccentric sheaves Ø30 at 3, 5 and 8 mm offset](https://xemstudio.com/objects/eccentric-sheaves/)
- [Scotch yoke: slotted yoke and crank disc, 20 and 30 mm stroke](https://xemstudio.com/objects/scotch-yoke/)