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HTD power pistons: Ø48.00 × 72 for the bored 2 in spool
What piston goes in a bored 2 inch tri-clamp spool? · Hardware · basis: Exact geometry at the finished bore Ø48.00
Long Earth Society build part. Parts of the HTD engines. 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
- 1 in table
Notes
- Ring-less: the seal is the fit. Two 8 lands carry it, 0.4 relief between them, 72 long (1.5 × bore) so it cannot cock. The crown faces the working space (down).
- The con-rod runs beside the axis (x 10.5..15.5) between two cheeks; the displacer rod passes up the centre tube (main piston) without touching the con-rod. The offset puts a small tilting moment on the piston, which the 72 length carries.
Sizes
| part | od_mm | length_mm | centre_bore_mm | pin |
|---|---|---|---|---|
| piston-48-rod6 | 48.0 | 72.0 | 6.0 | Ø5 at z 86, x 5..21 |
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 |
|---|---|---|---|---|
| OD | Ø48.00, two 8 lands | bored spool Ø48.00 (ring-less clearance seal) | run | all |
| centre bore | Ø6 × 72 | displacer rod (also the bleed to the crankcase) | run | piston-48-rod6* |
| pin bore | Ø5 in both cheeks | dowel-5x16 | press | all |
| cheek gap | 6.0 (x 10..16) | 5 thick con-rod (0.5 each side) | designed | 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
| piston-48-rod6 | Ø48.00 × 72 power piston: two 8 lands, 0.4 relief, 8 crown, Ø14 centre tube with the Ø6 displacer-rod bore, cross bar and two cheeks with a Ø5 pin bore 14 above the skirt (con-rod at x 10.5..15.5) | STEP · STL |
Plain text: sheet.txt · JSON: /api/geometry?object=htd-power-pistons
How it fits
In these build lists
HTD engine, 10 in tri-clamp…A big flat gamma Stirling for a propane burner: a Ø240 displacer in a 10 in weld…You might also need
Questions
How does the displacer rod get past the piston?
Through the piston's centre tube (Ø6 running fit, 72 long), which is also the bleed between working space and crankcase.