# Syringe cradle for 10, 20 and 60 mL barrels

> What are the dimensions of a cradle that holds a syringe as a Stirling power cylinder?

- Category: Stirling engines › Can & LTD engines
- Kind: Standard part
- Basis: Saddle drawn at the barrel OD of the plastic-syringes entries (10 mL Ø15.9, 20 mL Ø21.0, 60 mL Ø29.0); M3 clearance Ø3.4
- Page: https://xemstudio.com/objects/syringe-cradle/ · JSON: https://xemstudio.com/api/geometry?object=syringe-cradle · Plain text: https://xemstudio.com/objects/syringe-cradle/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 40 mm long block with a half-round saddle at the syringe barrel OD exactly (fit: socket): Ø15.9 for 10 mL, Ø21.0 for 20 mL, Ø29.0 for 60 mL.
- The saddle axis lies on the block's top face, so the block is barrel OD + 14 wide and half the barrel OD + 4 tall.
- Four Ø3.4 holes at x ±14 and y ±(OD/2 + 3.5) take M3 screws from the saddle face into the frame; at that spacing the screw heads clear the barrel.

## 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 |
|---|---|---|---|---|
| syringe cradle | Ø15.9 / Ø21.0 / Ø29.0 | 10 / 20 / 60 mL syringe barrel | socket | syringe-cradle-* |
| cradle screw holes | Ø3.4 | M3 screw clearance | designed | syringe-cradle-* |

## Sizes

| file | barrel OD | length | width | height |
|---|---|---|---|---|
| syringe-cradle-10ml | 15.9 | 40 | 29.9 | 11.95 |
| syringe-cradle-20ml | 21.0 | 40 | 35.0 | 14.5 |
| syringe-cradle-60ml | 29.0 | 40 | 43.0 | 18.5 |

## Where the files are

- Wikipedia: [Stirling engine](https://en.wikipedia.org/wiki/Stirling_engine) — web — CC BY-SA 4.0 (text)
- Long Earth Society: [Can engine build](https://longearthsociety.com/engineering/) — video, web — LES site
- Long Earth Society: [Engine builds (videos and write-ups)](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/syringe-cradle/index.json

- syringe-cradle-10ml: [STEP](https://xemstudio.com/files/hardware/can-engine-printed-kit/syringe-cradle-10ml.step) · [STL](https://xemstudio.com/files/hardware/can-engine-printed-kit/syringe-cradle-10ml.stl) — cradle for a 10ml syringe: 40 × 29.9 × 11.95, Ø15.9 half-trough for the barrel (exact), 4 × M3 clearance (Ø3.4) at 28 × 22.9 centres to the frame
- syringe-cradle-20ml: [STEP](https://xemstudio.com/files/hardware/can-engine-printed-kit/syringe-cradle-20ml.step) · [STL](https://xemstudio.com/files/hardware/can-engine-printed-kit/syringe-cradle-20ml.stl) — cradle for a 20ml syringe: 40 × 35 × 14.5, Ø21.0 half-trough for the barrel (exact), 4 × M3 clearance (Ø3.4) at 28 × 28 centres to the frame
- syringe-cradle-60ml: [STEP](https://xemstudio.com/files/hardware/can-engine-printed-kit/syringe-cradle-60ml.step) · [STL](https://xemstudio.com/files/hardware/can-engine-printed-kit/syringe-cradle-60ml.stl) — cradle for a 60ml syringe: 40 × 43 × 18.5, Ø29.0 half-trough for the barrel (exact), 4 × M3 clearance (Ø3.4) at 28 × 36 centres to the frame

## How it fits

### Goes in or on
- [Plastic syringes 1–60 mL as pistons and cylinders](https://xemstudio.com/objects/plastic-syringes/): barrel in the Ø15.9 / 21.0 / 29.0 saddle

### Connects to
- [Syringe pistons: ring-less pistons with a con-rod fork for 10, 20 and 30 mL syringe barrels](https://xemstudio.com/objects/syringe-pistons/): the piston that runs in the barrel
- [Can-engine cap for 53.3, 58, 66 and 76.2 mm cans](https://xemstudio.com/objects/can-engine-cap/): transfer tube from the cap's barb to the syringe tip

### Alternatives
- [Can-engine diaphragm: membrane, clamp rings and centre disc, Ø40 / 50 / 60](https://xemstudio.com/objects/can-engine-diaphragm/): diaphragm power piston instead

## Questions

**What diameter is a 10 mL syringe barrel?**

Ø15.9 outside, 14.5 inside; syringe-cradle-10ml's saddle is Ø15.9.

**How is the cradle fixed?**

Four M3 screws through Ø3.4 holes, 28 mm apart along the barrel.

## Fits with

- [Plastic syringes 1–60 mL as pistons and cylinders](https://xemstudio.com/objects/plastic-syringes/)
- [Syringe pistons: ring-less pistons with a con-rod fork for 10, 20 and 30 mL syringe barrels](https://xemstudio.com/objects/syringe-pistons/)
- [Can-engine cap for 53.3, 58, 66 and 76.2 mm cans](https://xemstudio.com/objects/can-engine-cap/)
- [Can-engine diaphragm: membrane, clamp rings and centre disc, Ø40 / 50 / 60](https://xemstudio.com/objects/can-engine-diaphragm/)
- [Build list: Soda-can gamma](https://xemstudio.com/objects/list-can-engine/)