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3 in crankcase caps: blind bearing cap, seal cap and 3-port cap
How do I put bearings and a shaft seal in a 3 inch tri-clamp cross? · Hardware · basis: Fabrication spec: 3 in cap profile with a Ø76.2 neck (the 20° back cone runs to the tube OD, then straight), bored and ported; exact geometry
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
- 3 in table
Notes
- Blind cap (−X branch): a 6001 at the end of a Ø36 boss that reaches 20 into the branch. Seal cap (+X): a 6001 at the boss end and another near the outer face, the shaft seal's housing (12 × 22 × 7) at the outer face, three M4 holes for the generator bracket.
- Port cap (top of the cross): three 1/4 NPT ports for the fill valve, the gauge and the relief valve. The crankcase is the bounce space: it reaches the working space's mean pressure through the piston's fit and the rod bore.
- The shaft seal is the one leak path to the outside of a charged engine: it has to be a seal rated for the relief pressure in that housing size, and a charged engine will still lose helium slowly through it.
Sizes
| part | thickness_mm | seats |
|---|---|---|
| bearing-cap-3in-blind-6001 | 28.0 | 6001 |
| seal-cap-3in-6001-seal12 | 30.0 | 2 × 6001 + seal 12 × 22 × 7 |
| port-cap-3in-3x-npt14 | 16.0 | 3 × 1/4 NPT |
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 |
|---|---|---|---|---|
| faces | ISO 2852 3 in (neck Ø76.2) | gasket-3in + 3 in clamp | clamp | all |
| bearing seats | Ø28 × 8 | bearing-6001 outer ring | press | bearing-cap-* |
| bearing seats | Ø28 × 8 (two) | bearing-6001 outer rings | press | seal-cap-* |
| seal housing | Ø22 × 7 | radial shaft seal 12 × 22 × 7 | press | seal-cap-* |
| shaft clearance | Ø14 | Ø12 shaft (no contact) | designed | all |
| bracket holes | 3 × M4 (drawn Ø4 × 10) on r 30 | shcs-m4x12 | designed | seal-cap-* |
| ports | 3 × 1/4-18 NPT, tap drill Ø11.1 × 11 | fill valve, gauge, relief valve (1/4 NPT male) | designed | port-cap-* |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| ASME | ASME B1.20.1 Pipe Threads (NPT): 1/8-27 and 1/4-18, tap drills Ø8.6 / Ø11.1 as on this site's thread envelopes | standard | ASME; dimensions are facts verify |
| Tameson (product listing) | Rotary shaft seal 12 × 22 × 7 mm (DIN 3760 sizes) | web | vendor page; dimensions are facts verify |
| Long Earth Society | Engine builds | web, video | LES site |
Free files
★ Free files 3 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json
| bearing-cap-3in-blind-6001 | 3 in blind bearing cap: ISO 2852 face, Ø76.2 neck to 28, inner boss Ø36 × 20 with a 6001 seat | STEP · STL |
| seal-cap-3in-6001-seal12 | 3 in seal cap: face, neck to 30, inner boss with a 6001 seat, a second 6001 seat 14..22, 12 × 22 × 7 shaft-seal housing at the outer face, 3 × M4 tapped on r 30 | STEP · STL |
| port-cap-3in-3x-npt14 | 3 in port cap: neck to 16, three 1/4 NPT ports on r 20 (fill valve, gauge, relief valve) | STEP · STL |
Plain text: sheet.txt · JSON: /api/geometry?object=htd-crankcase-caps-3in
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
Where do the fill valve, gauge and relief valve go?
In the 3 in port cap on top of the crankcase cross; the working space follows through the piston's fit.