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Can-engine diaphragm: membrane, clamp rings and centre disc, Ø40 / 50 / 60
What are the dimensions of the diaphragm clamp rings for a can Stirling engine? · Standard part · basis: Ring bore = diaphragm working diameter; centre disc at half the bore; 6 × M3 clearance (ISO 273) on the ring
Long Earth Society build part. The printed parts for the LES can engine, sized to the cans, syringes, CDs and bearings in the library. The engines
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. Mating features
- sizes
- 3 in table
Notes
- The diaphragm power piston of the can engine: a 0.2 mm membrane clamped round its edge between two identical rings, with a stiff centre disc the con-rod screws to.
- Rings come in Ø40, Ø50 and Ø60 bores, each 3 thick with an outside of bore + 16 (Ø56 / 66 / 76) and 6 × Ø3.4 holes on a bore + 8 circle (Ø48 / 58 / 68).
- Each ring size has its own centre disc at half the bore: Ø20, Ø25 or Ø30 × 2 with a Ø3.2 hole for the M3 con-rod screw.
- Each membrane is the rings' outside diameter (Ø56 / 66 / 76) × 0.2 with the same six Ø3.4 holes and a Ø3.2 centre hole; its free span is the ring bore. One membrane, two rings and one disc of the same size make one diaphragm.
Sizes
| size | ring bore | ring outside | screw circle | ring thickness | disc | disc hole |
|---|---|---|---|---|---|---|
| 40 | 40 | 56 | 48 | 3 | Ø20 × 2 | 3.2 |
| 50 | 50 | 66 | 58 | 3 | Ø25 × 2 | 3.2 |
| 60 | 60 | 76 | 68 | 3 | Ø30 × 2 | 3.2 |
Mating features
Drawn at the exact size. Open press, slide, run and socket features by your process's clearance; leave designed gaps and clamp fits as drawn.
| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| clamp-ring screw holes | Ø3.4 | M3 screw clearance | designed | diaphragm-ring-* |
| centre-disc screw hole | Ø3.2 | M3 screw clearance (ISO 273 fine) | designed | diaphragm-disc-* |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| Wikipedia | Stirling engine | web | CC BY-SA 4.0 (text) |
| Long Earth Society | Can engine build | video, web | LES site |
| Long Earth Society | Engine builds (videos and write-ups) | web, video | LES site |
Free files
★ Free files 9 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json
| diaphragm-ring-40 | diaphragm clamp ring Ø40 bore × Ø56, 3 thick, 6 × Ø3.4 (M3 clearance); two per diaphragm, one each side of the membrane | STEP · STL |
| diaphragm-disc-20 | diaphragm centre disc Ø20 × 2, Ø3.2 M3 clearance hole for the con-rod screw | STEP · STL |
| diaphragm-membrane-40 | diaphragm membrane Ø56 × 0.2 with the rings' 6 × Ø3.4 holes and a Ø3.2 centre hole; free span Ø40 between the rings | STEP · STL |
| diaphragm-ring-50 | diaphragm clamp ring Ø50 bore × Ø66, 3 thick, 6 × Ø3.4 (M3 clearance); two per diaphragm, one each side of the membrane | STEP · STL |
| diaphragm-disc-25 | diaphragm centre disc Ø25 × 2, Ø3.2 M3 clearance hole for the con-rod screw | STEP · STL |
| diaphragm-membrane-50 | diaphragm membrane Ø66 × 0.2 with the rings' 6 × Ø3.4 holes and a Ø3.2 centre hole; free span Ø50 between the rings | STEP · STL |
| diaphragm-ring-60 | diaphragm clamp ring Ø60 bore × Ø76, 3 thick, 6 × Ø3.4 (M3 clearance); two per diaphragm, one each side of the membrane | STEP · STL |
| diaphragm-disc-30 | diaphragm centre disc Ø30 × 2, Ø3.2 M3 clearance hole for the con-rod screw | STEP · STL |
| diaphragm-membrane-60 | diaphragm membrane Ø76 × 0.2 with the rings' 6 × Ø3.4 holes and a Ø3.2 centre hole; free span Ø60 between the rings | STEP · STL |
Plain text: sheet.txt · JSON: /api/geometry?object=can-engine-diaphragm
How it fits
Connects to
Con-rods with Ø3 pin ends, 45 and 60 mm, 8 × 5con-rod screwed to the centre disc's Ø3.2 holeAlternatives
Syringe cradle for 10, 20 and 60 mL barrelsa syringe as the power piston insteadAlso needed
Socket head cap screws, M2–M86 × M3 through the rings, 1 × M3 in the discYou might also need
Questions
Which centre disc goes with which ring?
Half the ring bore: Ø20 disc with the Ø40 rings, Ø25 with Ø50, Ø30 with Ø60.
How are the diaphragm rings fastened?
Six M3 screws through Ø3.4 holes on a circle 8 mm larger than the bore (Ø58 on the 50 mm ring), through both rings and the membrane.
Which size does the can engine use?
The can-engine build list uses the Ø50 rings with the Ø25 disc.