# Chamber rings Ø100 and Ø150 × 20

> What ring makes a shallow 100 or 150 mm chamber between two plates?

- Category: Hardware › Plates & discs
- Kind: Hardware
- Basis: Chamber height 20: an 8 mm displacer at 10 mm stroke (crank-disc-b3-stroke10) with 1 mm at each end; M3 tap drill Ø2.5
- Page: https://xemstudio.com/objects/chamber-rings-100-150/ · JSON: https://xemstudio.com/api/geometry?object=chamber-rings-100-150 · Plain text: https://xemstudio.com/objects/chamber-rings-100-150/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

- The wall of the LTD displacer chamber, between the bottom and top plates. Bore Ø100 or Ø150, 20 tall, 10 mm wall (outside Ø120 / Ø170).
- Six Ø2.5 holes (M3 tap drill) through its height on a Ø112 / Ø162 circle: an M3 × 12 comes in from each plate.
- The displacer runs inside with a 2 mm radial gap by design; nothing moving touches the ring.

## 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 |
|---|---|---|---|---|
| chamber-ring screw holes | Ø2.5 through | M3 tap drill (an M3 × 12 from each plate) | designed | ltd-100-chamber* |
| chamber-ring screw holes | Ø2.5 through | M3 tap drill (an M3 × 12 from each plate) | designed | ltd-150-chamber* |

## Sizes

| file | bore | outside | height | screw circle |
|---|---|---|---|---|
| ltd-100-chamber-ring-h20 | 100 | 120 | 20 | 112 |
| ltd-150-chamber-ring-h20 | 150 | 170 | 20 | 162 |

## Where the files are

- Wikipedia: [Stirling engine](https://en.wikipedia.org/wiki/Stirling_engine) — web — CC BY-SA 4.0 (text)
- James R. Senft: [An Introduction to Low Temperature Differential Stirling Engines](https://www.stirlingengine.com/) — book — Moriya Press (verify at link)
- 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/chamber-rings-100-150/index.json

- ltd-100-chamber-ring-h20: [STEP](https://xemstudio.com/files/hardware/chamber-rings-100-150/ltd-100-chamber-ring-h20.step) · [STL](https://xemstudio.com/files/hardware/chamber-rings-100-150/ltd-100-chamber-ring-h20.stl) — chamber ring Ø100 bore × 20 tall, 10 mm wall, 6 × Ø2.5 (M3 tapped) through on a Ø112 circle; the displacer runs inside
- ltd-150-chamber-ring-h20: [STEP](https://xemstudio.com/files/hardware/chamber-rings-100-150/ltd-150-chamber-ring-h20.step) · [STL](https://xemstudio.com/files/hardware/chamber-rings-100-150/ltd-150-chamber-ring-h20.stl) — chamber ring Ø150 bore × 20 tall, 10 mm wall, 6 × Ø2.5 (M3 tapped) through on a Ø162 circle; the displacer runs inside

## How it fits

### Connects to
- [Top plates Ø120 and Ø170 with a syringe socket](https://xemstudio.com/objects/round-top-plates-syringe-socket/): top face, 6 × M3
- [Bottom plates Ø120 and Ø170](https://xemstudio.com/objects/round-bottom-plates-120-170/): bottom face, 6 × M3
- [Flat discs Ø96 × 8 and Ø146 × 8 on a rod](https://xemstudio.com/objects/flat-discs-on-rod-96-146/): displacer inside, 2 mm radial gap

## Questions

**How tall is the chamber of the LTD Stirling engine here?**

20 mm, for an 8 mm thick displacer moving 10 mm: 1 mm to spare at each end.

**What displacer goes in the Ø100 chamber ring?**

The Ø96 × 8 LTD displacer: 2 mm radial gap, designed.

## Fits with

- [Top plates Ø120 and Ø170 with a syringe socket](https://xemstudio.com/objects/round-top-plates-syringe-socket/)
- [Bottom plates Ø120 and Ø170](https://xemstudio.com/objects/round-bottom-plates-120-170/)
- [Flat discs Ø96 × 8 and Ø146 × 8 on a rod](https://xemstudio.com/objects/flat-discs-on-rod-96-146/)