# Swash (wobble) plate: Ø40 plates at 10, 15 and 20° with a ball-end follower

> How do I make a swash plate (wobble plate) drive with 3D printed parts?

- Category: Stirling engines › Drives & mechanisms
- Kind: Hardware
- Basis: Swash plate geometry: a follower at radius r on a plate tilted θ moves r·sin θ each side (stroke 2r·sin θ); Ø5 shaft
- Page: https://xemstudio.com/objects/swash-plate/ · JSON: https://xemstudio.com/api/geometry?object=swash-plate · Plain text: https://xemstudio.com/objects/swash-plate/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 disc fixed at an angle on a shaft; a follower pressed against it reciprocates once per turn.
- Stroke = 2 × r × sin θ for a follower at radius r. At the Ø40 rim: 6.9 mm at 10°, 10.4 mm at 15°, 13.7 mm at 20°.
- Several followers spaced around one plate drive several cylinders from one shaft.
- The follower is an 8 mm square pushrod with a Ø8 ball end and a Ø3 hole in its tail.

## 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-* |
| follower tail hole | Ø3 | Ø3 pin | run | swash-follower-* |

## Sizes

| plate | tilt | stroke at rim (r 20) | stroke at r 18 |
|---|---|---|---|
| Ø40 | 10° | 6.9 mm | 6.3 mm |
| Ø40 | 15° | 10.4 mm | 9.3 mm |
| Ø40 | 20° | 13.7 mm | 12.3 mm |

## 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 (4 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/swash-plate/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
- swash-follower-8x30: [STEP](https://xemstudio.com/files/hardware/swash-plate/swash-follower-8x30.step) · [STL](https://xemstudio.com/files/hardware/swash-plate/swash-follower-8x30.stl) — swash follower: 8 mm square pushrod with a Ø8 ball end, Ø3 tail hole

## How it fits

### Goes in or on
- [Stirling shafts and rods: Ø3 rods, Ø5 / Ø8 D-flat crankshafts, Ø5 tube rods, Ø3 pins, thrust spacers](https://xemstudio.com/objects/stirling-shafts-and-rods/): Ø5 shaft through the hub

### Alternatives
- [Scotch yoke: slotted yoke and crank disc, 20 and 30 mm stroke](https://xemstudio.com/objects/scotch-yoke/): single-cylinder sine motion
- [Eccentric and strap: Ø30 eccentrics at 3, 5 and 8 mm offset with a split strap](https://xemstudio.com/objects/eccentric-and-strap/): single strap drive

### Also needed
- [Shafts, D-flats, set-screw collars, E-clips (DIN 6799) and circlips (DIN 471)](https://xemstudio.com/objects/shaft-collars-clips-and-shafts/): locate the plate on the shaft

## Questions

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

Stroke = 2 × r × sin θ for a follower at radius r on a plate tilted θ: Ø40 plate, follower at r = 18, 15° gives 9.3 mm.

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

Yes. Space followers around the plate; each one reaches top of stroke at a different shaft angle, set by its position around the plate.

## Fits with

- [Stirling shafts and rods: Ø3 rods, Ø5 / Ø8 D-flat crankshafts, Ø5 tube rods, Ø3 pins, thrust spacers](https://xemstudio.com/objects/stirling-shafts-and-rods/)
- [Shafts, D-flats, set-screw collars, E-clips (DIN 6799) and circlips (DIN 471)](https://xemstudio.com/objects/shaft-collars-clips-and-shafts/)
- [Ball bearings, 683 to 6210 and flanged F6xx (ISO 15)](https://xemstudio.com/objects/ball-bearings-metric/)
- [Scotch yoke: slotted yoke and crank disc, 20 and 30 mm stroke](https://xemstudio.com/objects/scotch-yoke/)
- [Eccentric and strap: Ø30 eccentrics at 3, 5 and 8 mm offset with a split strap](https://xemstudio.com/objects/eccentric-and-strap/)