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Alpha V-twin crank disc Ø26, one pin, 16 mm stroke
What crank disc does a 90° V-twin alpha Stirling use? · Hardware · basis: 90° V alpha: both con-rods on one pin; throw 8 (stroke 16)
Long Earth Society build part. The two-syringe alpha, complete. 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
- 6 in table
Notes
- Ø26 × 6 disc with a Ø5 bore (fit: slide) and a Ø2.5 radial hole (M3 tap size) for the grub screw.
- ONE Ø3 hole (fit: press) at 8 mm for a Ø3 × 20 crank pin; both con-rods ride it, one plane each, with 1 mm spacers and a 3 mm collar on the end.
- A two-pin disc with pins 90° apart under a 90° V would give 0° or 180° and the engine would not run; that disc is for parallel cylinders.
Sizes
| parameter | value |
|---|---|
| disc | Ø26 × 6 |
| bore | Ø5 |
| throw | 8 |
| stroke | 16 |
| pin hole | 1 × Ø3 |
| grub hole | Ø2.5 |
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 |
|---|---|---|---|---|
| crank-disc bore | Ø5 | Ø5 crankshaft (M3 grub) | slide | alpha-crank-disc-* |
| crank-disc pin hole | Ø3 | Ø3 × 20 crank pin | press | alpha-crank-disc-* |
| crank-disc grub hole | Ø2.5 | M3 tap drill | designed | alpha-crank-disc-* |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| Long Earth Society | Engine builds | web, video | LES site |
| Wikipedia | Stirling engine (alpha configuration) | web | CC BY-SA 4.0 (text) |
Free files
★ Free files 1 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json
| alpha-crank-disc-s16 | crank disc Ø26 × 6, Ø5 bore, Ø2.5 tap-drill hole for an M3 grub, ONE Ø3 pin at 8 mm (stroke 16): both con-rods share it | STEP · STL |
Plain text: sheet.txt · JSON: /api/geometry?object=alpha-v-twin-crank-disc
How it fits
Goes in or on
Alpha V-twin frame for two 10 mL syringes at 90°on the shaft beside the bossConnects to
Con-rods with Ø3 pin ends, 45 and 60 mm, 8 × 5both alpha-conrod-60s on the one Ø3 pin
Crankshafts Ø3, Ø5 and Ø8 with full-length D-flatØ5 × 80 crankshaft, Ø3 × 20 pinAlternatives
Two-pin crank disc, pins 90° apart, 6 / 8 / 10 mm…for parallel cylindersIn these build lists
Alpha V-twin, two 10 mL syringesTwo 10 mL syringe barrels in a 90° V on one crank pin: the V is the 90° phase.You might also need
Questions
Does a V-twin alpha need two crank pins?
No. In a 90° V both rods share one pin; the V gives the 90° phase.
What stroke does the alpha crank disc give?
16 mm (pin at 8 mm), about 2.6 mL per 10 mL syringe.