# Can-engine cap for 53.3, 58, 66 and 76.2 mm cans

> What are the dimensions of the cap for a soda-can Stirling engine?

- Category: Stirling engines › Can & LTD engines
- Kind: Standard part
- Basis: Bore drawn at the can body OD of the can entries (Ø66 12 oz, Ø58 sleek, Ø53.3 slim, Ø76.2 steel 300); rod bore at the 2 mm rod, hose barb at the barb-4mm profile
- Page: https://xemstudio.com/objects/can-engine-cap/ · JSON: https://xemstudio.com/api/geometry?object=can-engine-cap · Plain text: https://xemstudio.com/objects/can-engine-cap/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 cap closes the open end of the can and is the cold end of the can engine's displacer cylinder. Its bore is the can body OD exactly (Ø66, Ø58, Ø53.3 or Ø76.2), 11 mm deep, under a 3 mm top wall; the outside is the can OD + 4.8 (Ø70.8 for the 66 mm can).
- On centre a Ø16 boss carries a Ø2 bore straight through for the 2 mm displacer rod (fit: run). The bore is the rod guide and the seal; nothing is pressed into it.
- The transfer port is an integral Ø4 hose barb, the same profile as barb-4mm on the silicone tube page, set 0.3 × the can diameter off centre (19.8 mm on the 66 mm cap); the 4 × 6 transfer tube goes from it to the power cylinder.
- Three Ø2.5 holes (M3 tap size) at 120°, 6 mm above the open face, take grub screws that grip the can wall. Every mating size is in the Mating features table.

## 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 |
|---|---|---|---|---|
| can-cap bore | Ø66 / Ø58 / Ø53.3 / Ø76.2 | can body OD (three M3 grubs grip it) | slide | can-cap-* |
| grub holes | Ø2.5 | M3 tap drill | designed | can-cap-* |
| rod-guide bore | Ø2 × 6 | 2 mm wire displacer rod | run | can-cap-* |
| transfer-port barb | Ø4 shank, 3 ridges to Ø5.2, Ø2.5 bore, 14 proud | 4 mm ID tube | designed | can-cap-* |

## Sizes

| file | can | bore | outside Ø | height |
|---|---|---|---|---|
| can-cap-66 | 12 oz standard | 66.0 | 70.8 | 17 |
| can-cap-58 | sleek | 58.0 | 62.8 | 17 |
| can-cap-53.3 | slim | 53.3 | 58.1 | 17 |
| can-cap-76.2 | steel 300 food can | 76.2 | 81.0 | 17 |

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

Index: https://xemstudio.com/files/hardware/can-engine-cap/index.json

- can-cap-66: [STEP](https://xemstudio.com/files/hardware/can-engine-printed-kit/can-cap-66.step) · [STL](https://xemstudio.com/files/hardware/can-engine-printed-kit/can-cap-66.stl) — cap for a Ø66 can: bore Ø66 (the can body OD, exact), Ø2 rod-guide bore for the 2 mm wire rod, integral transfer-port barb for 4 mm ID tube (Ø4 shank, three ridges to Ø5.2, Ø2.5 bore, 14 proud), 3 × M3 tapped (Ø2.5) grub holes
- can-cap-58: [STEP](https://xemstudio.com/files/hardware/can-engine-printed-kit/can-cap-58.step) · [STL](https://xemstudio.com/files/hardware/can-engine-printed-kit/can-cap-58.stl) — cap for a Ø58 can: bore Ø58 (the can body OD, exact), Ø2 rod-guide bore for the 2 mm wire rod, integral transfer-port barb for 4 mm ID tube (Ø4 shank, three ridges to Ø5.2, Ø2.5 bore, 14 proud), 3 × M3 tapped (Ø2.5) grub holes
- can-cap-53.3: [STEP](https://xemstudio.com/files/hardware/can-engine-printed-kit/can-cap-53.3.step) · [STL](https://xemstudio.com/files/hardware/can-engine-printed-kit/can-cap-53.3.stl) — cap for a Ø53.3 can: bore Ø53.3 (the can body OD, exact), Ø2 rod-guide bore for the 2 mm wire rod, integral transfer-port barb for 4 mm ID tube (Ø4 shank, three ridges to Ø5.2, Ø2.5 bore, 14 proud), 3 × M3 tapped (Ø2.5) grub holes
- can-cap-76.2: [STEP](https://xemstudio.com/files/hardware/can-engine-printed-kit/can-cap-76.2.step) · [STL](https://xemstudio.com/files/hardware/can-engine-printed-kit/can-cap-76.2.stl) — cap for a Ø76.2 can: bore Ø76.2 (the can body OD, exact), Ø2 rod-guide bore for the 2 mm wire rod, integral transfer-port barb for 4 mm ID tube (Ø4 shank, three ridges to Ø5.2, Ø2.5 bore, 14 proud), 3 × M3 tapped (Ø2.5) grub holes

## How it fits

### Parts that fit it
- [CD / DVD disc Ø120 × 1.2 mm with Ø15 hole (and mini CD Ø80)](https://xemstudio.com/objects/cd-dvd-discs/): Ø15 hole on the hub's Ø15.0 spigot
- [Hard-drive platters: 3.5 in Ø95 × 1.27 mm (Ø25 hole), 2.5 in Ø65 × 0.8 mm (Ø20 hole)](https://xemstudio.com/objects/hdd-platters/): Ø25 hole on the hub's Ø25.0 spigot
- [Bamboo skewer Ø3 × 300 mm](https://xemstudio.com/objects/bamboo-skewers/): the can engine's crankshaft
- [Coat-hanger wire Ø2.0 mm and paper-clip wire Ø1.0 mm](https://xemstudio.com/objects/coat-hanger-and-paper-clip-wire/): 2 mm wire rod through the Ø2 bore in the can cap (run)
- [BBs: steel Ø4.5 mm (.177) and airsoft Ø6.0 mm](https://xemstudio.com/objects/steel-and-airsoft-bbs/): BBs as guides along the displacer rod
- [Ping-pong ball Ø40 mm, 0.4 mm wall](https://xemstudio.com/objects/ping-pong-ball/): lightweight displacer in a small demonstrator
- [Hose barbs for 2, 3, 4, 6 and 8 mm ID tube](https://xemstudio.com/objects/hose-barbs/): the cap's integral Ø4 barb uses this profile
- [Displacer rods Ø2 × 60, 78, 100 and 180, Ø3 × 100, 150 and 200](https://xemstudio.com/objects/displacer-rods/): Ø2 rod in the cap's Ø2 bore

### Goes in or on
- [Aluminium beverage cans: 12 oz standard, 16 oz, 330/500 mL, sleek, slim, mini](https://xemstudio.com/objects/beverage-cans/): Ø66 bore over the 12 oz can body
- [Steel food cans: soup, vegetable, tuna, #2, #2½, #10, coffee](https://xemstudio.com/objects/steel-food-cans/): Ø76.2 bore over the steel 300 can

### Connects to
- [Can-engine displacer Ø54 × 25, Ø62 × 30, Ø72 × 35](https://xemstudio.com/objects/can-engine-displacer/): the displacer's 2 mm rod runs in the cap's Ø2 bore
- [Silicone tube 1 × 3 to 10 × 14 mm (ID × OD)](https://xemstudio.com/objects/silicone-tube/): 4 × 6 tube on the integral Ø4 barb
- [Syringe cradle for 10, 20 and 60 mL barrels](https://xemstudio.com/objects/syringe-cradle/): transfer tube from the cap's barb to the syringe tip

### Also needed
- [Craft sticks 114 × 10 × 2 mm and jumbo 150 × 18 × 2 mm](https://xemstudio.com/objects/craft-sticks/): 2 mm wire displacer rod

## Questions

**What size cap fits a 12 oz soda can?**

Can-cap-66: Ø66.0 bore (the can body OD), 11 mm deep, Ø70.8 outside, 17 mm tall overall.

**How does the displacer rod pass through the cap?**

Through a Ø2 bore straight through the Ø16 centre boss, drawn at the 2 mm rod (fit: run); the bore itself is the guide.

**Where does the transfer tube connect?**

To the integral Ø4 hose barb (barb-4mm profile) 0.3 × the can diameter off centre, 19.8 mm on the 66 mm cap.

## Fits with

- [Can-engine displacer Ø54 × 25, Ø62 × 30, Ø72 × 35](https://xemstudio.com/objects/can-engine-displacer/)
- [Crank stand for a 623 bearing, 40 / 60 / 80 mm](https://xemstudio.com/objects/can-engine-crank-stand/)
- [Syringe cradle for 10, 20 and 60 mL barrels](https://xemstudio.com/objects/syringe-cradle/)
- [Aluminium beverage cans: 12 oz standard, 16 oz, 330/500 mL, sleek, slim, mini](https://xemstudio.com/objects/beverage-cans/)
- [Silicone tube 1 × 3 to 10 × 14 mm (ID × OD)](https://xemstudio.com/objects/silicone-tube/)
- [Build list: Soda-can gamma](https://xemstudio.com/objects/list-can-engine/)