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Flywheel crank: Ø100 nut-pocket flywheel with a 7.5 mm crank pin (15 mm stroke)
Can a Stirling engine's flywheel carry the crank pin? · Hardware · basis: The Ø100 M8 nut-pocket flywheel (tools/gen_shafts_flywheels.py) with one added Ø3 pin hole through the hub at 7.5 from the axis
Long Earth Society build part. Flywheel and crank in one for the mug LTD and the test-tube marble engine. 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
- 4 in table
Notes
- Same wheel as flywheel-100-m8-b3 (12 M8 pockets at R40.5, Ø3 hub with M3 grub), plus a Ø3 hole through the hub at 7.5 from the axis, 90° from the grub, for a dowel-3x16 crank pin (10 in the hub, through a 5 mm con-rod, 1 proud). Overhung at a shaft end with the hub toward the con-rod: on the mug LTD it is the displacer crank (the web on the far side, so the displacer clevis passes under the rim); on the test-tube marble engine it drives the rocking link.
- Six M8 nuts in alternate pockets to start.
Sizes
| feature | value_mm |
|---|---|
| diameter | 100 |
| crank throw | 7.5 |
| pin hole | Ø3 through the 12.3 hub |
| bore | Ø3 |
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 |
|---|---|---|---|---|
| hub bore | Ø3 | Ø3 shaft (crankshaft or dowel-3x30) | slide | all |
| crank-pin hole | Ø3, 7.5 from the axis | dowel-3x16 crank pin | press | all |
| grub hole | Ø2.5 (M3 tapped) | set-m3x8 | designed | all |
| nut pockets | 12 × M8 hex, one flat outward | M8 hex nut (flywheel weight) | press | all |
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 |
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
| flywheel-crank-100-m8-b3-s15 | Ø100 flywheel with 12 M8 nut pockets (the nut-pocket flywheel's geometry, Ø3 hub, M3 grub) and a Ø3 crank-pin hole through the hub 7.5 from the axis (15 mm stroke), 90° from the grub | STEP · STL |
Plain text: sheet.txt · JSON: /api/geometry?object=flywheel-crank
How it fits
In these build lists
Mug LTD (sits on a coffee mug)Test-tube marble enginecrank and flywheel at the end.You might also need
Questions
Why put the crank pin in the flywheel?
The mug LTD's two cylinders are only 35 mm apart; with both cranks overhung there is no room for a separate flywheel on the shaft, so the flywheel is the displacer crank.