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Tri-clamp cups: closed-end spools (ferrule on a capped tube), 1.5, 2 and 3 in
What are the dimensions of a 2 inch tri-clamp spool with one end welded shut? · Hardware · basis: ISO 2852 ferrule face (C2/C3, 2.85 mm rim, 1.6 mm recess, 20° back) and 16 ga ASME BPE tube from the tri-clamp ferrule entry; 3 mm flat end plate standing in for a welded cap
Long Earth Society build part. The closed-end cylinder of the tri-clamp engines, as one part. The engines
- sizes
- 13 in table
Notes
- A cup is a spool with one ferrule and the other end closed: in stainless it is a tube with a cap welded on (or a 'tri-clamp end cap spool', sold as such); here it is one printed part. The ferrule end takes a stock clamp and gasket against any head on this shelf.
- What it is for: the hot end of a beta or gamma engine (the cup is the displacer cylinder, the open ferrule end gets the cold head with the rod guide), an alpha cylinder with the piston in it and the head carrying the con-rod gland, a cold-side water jacket cap, or a mock-up to check lengths before buying steel.
- Printed cups are cold-side and mock-up parts: PETG is good to ~70 °C. For a burner-fired hot end buy a stainless capped spool and use the printed one to set the length. Inner diameter matches the steel (34.8 / 47.5 / 72.9), so the displacers and pistons on this shelf fit both.
- Print closed end down, 0.2 mm layers, 3+ walls; the ferrule's 20° back cone needs no supports. Sand the face flat on a sheet of 400 grit on glass so the gasket seals.
- Lengths: 1.5 in 50/75/100, 2 in 60/90/120/150, 3 in 80/120/160; the -rod3 version has a Ø3.2 centre hole in the end for a displacer rod gland on the closed end (beta engines with the drive on the hot side are rare; it is there for a cold-end cup).
Sizes
| size | od_mm | id_mm | length_mm | end_plate_mm | end |
|---|---|---|---|---|---|
| 1.5 | 38.1 | 34.8 | 50 | 3.0 | plain |
| 1.5 | 38.1 | 34.8 | 75 | 3.0 | plain |
| 1.5 | 38.1 | 34.8 | 100 | 3.0 | plain |
| 1.5 | 38.1 | 34.8 | 75 | 3.0 | Ø3.2 centre hole |
| 2 | 50.8 | 47.5 | 60 | 3.0 | plain |
| 2 | 50.8 | 47.5 | 90 | 3.0 | plain |
| 2 | 50.8 | 47.5 | 120 | 3.0 | plain |
| 2 | 50.8 | 47.5 | 150 | 3.0 | plain |
| 2 | 50.8 | 47.5 | 90 | 3.0 | Ø3.2 centre hole |
| 3 | 76.2 | 72.9 | 80 | 3.0 | plain |
| 3 | 76.2 | 72.9 | 120 | 3.0 | plain |
| 3 | 76.2 | 72.9 | 160 | 3.0 | plain |
| 3 | 76.2 | 72.9 | 120 | 3.0 | Ø3.2 centre hole |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| ISO | ISO 2852:1993 Stainless steel clamp pipe couplings for the food industry | standard | ISO verify |
| Long Earth Society | Tri-clamp Stirling engine builds | web, video | LES site |
Free files
★ Free files 13 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json
| cup-1.5in-50 | 1.5 in closed-end spool Ø38.1 × 50: ISO 2852 ferrule face, 16 ga wall, 3 mm closed end with a 1.5 mm outer fillet (the weld); print closed end down | STEP · STL |
| cup-1.5in-75 | 1.5 in closed-end spool Ø38.1 × 75: ISO 2852 ferrule face, 16 ga wall, 3 mm closed end with a 1.5 mm outer fillet (the weld); print closed end down | STEP · STL |
| cup-1.5in-100 | 1.5 in closed-end spool Ø38.1 × 100: ISO 2852 ferrule face, 16 ga wall, 3 mm closed end with a 1.5 mm outer fillet (the weld); print closed end down | STEP · STL |
| cup-1.5in-75-rod3 | 1.5 in closed-end spool × 75 with a Ø3.2 centre hole in the end for a displacer rod or gland | STEP · STL |
| cup-2in-60 | 2 in closed-end spool Ø50.8 × 60: ISO 2852 ferrule face, 16 ga wall, 3 mm closed end with a 1.5 mm outer fillet (the weld); print closed end down | STEP · STL |
| cup-2in-90 | 2 in closed-end spool Ø50.8 × 90: ISO 2852 ferrule face, 16 ga wall, 3 mm closed end with a 1.5 mm outer fillet (the weld); print closed end down | STEP · STL |
| cup-2in-120 | 2 in closed-end spool Ø50.8 × 120: ISO 2852 ferrule face, 16 ga wall, 3 mm closed end with a 1.5 mm outer fillet (the weld); print closed end down | STEP · STL |
| cup-2in-150 | 2 in closed-end spool Ø50.8 × 150: ISO 2852 ferrule face, 16 ga wall, 3 mm closed end with a 1.5 mm outer fillet (the weld); print closed end down | STEP · STL |
| cup-2in-90-rod3 | 2 in closed-end spool × 90 with a Ø3.2 centre hole in the end for a displacer rod or gland | STEP · STL |
| cup-3in-80 | 3 in closed-end spool Ø76.2 × 80: ISO 2852 ferrule face, 16 ga wall, 3 mm closed end with a 1.5 mm outer fillet (the weld); print closed end down | STEP · STL |
| cup-3in-120 | 3 in closed-end spool Ø76.2 × 120: ISO 2852 ferrule face, 16 ga wall, 3 mm closed end with a 1.5 mm outer fillet (the weld); print closed end down | STEP · STL |
| cup-3in-160 | 3 in closed-end spool Ø76.2 × 160: ISO 2852 ferrule face, 16 ga wall, 3 mm closed end with a 1.5 mm outer fillet (the weld); print closed end down | STEP · STL |
| cup-3in-120-rod3 | 3 in closed-end spool × 120 with a Ø3.2 centre hole in the end for a displacer rod or gland | STEP · STL |
Plain text: sheet.txt · JSON: /api/geometry?object=tri-clamp-cups
How it fits
Connects to
Tri-clamp clamps, hot-joint gaskets and heat shieldsclamps its ferrule face to any headAlternatives
Tri-clamp spool, 1.5 and 2 inchspool + flat end cap
Tri-clamp end cap and gasket, 1.5 and 2 inchcap a plain spoolAlso needed
Tri-clamp displacers and engine headsdisplacer and cold head
Tri-clamp power pistons and crank linkagealpha cylinder pistonIn these build lists
Free-piston Stirling, 2 in tri-clampNo crank: displacer rod through the piston, both hung on spiral flexure stacks; …You might also need
Questions
Can I use a printed tri-clamp cup as the hot end of a Stirling engine?
Only on a hot-plate or warm-water engine (under ~70 °C for PETG). For a tea light or burner use a stainless capped spool; print the cup to set the length and test the fit first.
What is the inside diameter of a 2 inch tri-clamp cup?
47.5 mm, the same as a 16 ga 2 in spool, so the Ø46 displacer and the Ø47.3 lapped piston both fit.
How do I print the ferrule face so it seals?
Face up, closed end on the bed; afterwards rub the face on 400 grit on glass until it is uniformly matte, then clamp with a stock gasket.