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LTD Stirling top plate with syringe socket, Ø120 and Ø170
What are the dimensions of the top plate of a coffee-cup (LTD) Stirling engine? · Hardware · basis: Senft LTD gamma layout, sized in the assembled Ø100 engine on this site; syringe socket at the 10 mL barrel OD Ø15.9; rod bore at the 2 mm rod; M3 clearance Ø3.4 (ISO 273), M3 tap drill Ø2.5
Long Earth Society build part. The warm-hand demonstrator. 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
- 2 in table
Notes
- The cold plate of the LTD engine and its power cylinder mount. Ø120 (for the 100 chamber) or Ø170 (for the 150 chamber), 3 thick, with 6 × Ø3.4 on a Ø112 / Ø162 circle (at 30°, 90°, …) matching the chamber ring.
- At x −5 a Ø20 boss, 13 tall with the plate, has a Ø2 bore straight through for the 2 mm displacer rod (fit: run); the bore is the rod guide.
- At x 40 (45 from the rod guide, so the two con-rods can sit at the two ends of the crankshaft) a Ø21.9 boss rises to 20 mm with a Ø15.9 socket from 8 to 20 for a 10 mL syringe barrel (fit: socket) and a Ø10 port under it into the chamber: the barrel's closed end sits on the socket floor and its Luer tip ends flush with the plate's underside.
- Four Ø9 × 4 pads at (7.5, ±27) and (27.5, ±27) carry the two crank stands, each with an M3 tapped hole (Ø2.5) 6 deep.
Sizes
| file | plate | screw circle | rod guide | syringe socket | height |
|---|---|---|---|---|---|
| ltd-100-top-plate-syringe | Ø120 × 3 | 112 | Ø2 × 13 at x −5 | Ø15.9 × 12 at x 40 | 20 |
| ltd-150-top-plate-syringe | Ø170 × 3 | 162 | Ø2 × 13 at x −5 | Ø15.9 × 12 at x 40 | 20 |
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 |
|---|---|---|---|---|
| syringe socket | Ø15.9 | 10 mL syringe barrel | socket | ltd-100-top* |
| syringe socket | Ø15.9 | 10 mL syringe barrel | socket | ltd-150-top* |
| plate screw holes | Ø3.4 | M3 screw clearance (ISO 273) | designed | ltd-100-top* |
| plate screw holes | Ø3.4 | M3 screw clearance (ISO 273) | designed | ltd-150-top* |
| stand pad holes | Ø2.5 × 6 | M3 tap drill | designed | ltd-100-top* |
| stand pad holes | Ø2.5 × 6 | M3 tap drill | designed | ltd-150-top* |
| syringe port under the socket | Ø10 | syringe tip (no contact) | designed | ltd-100-top* |
| syringe port under the socket | Ø10 | syringe tip (no contact) | designed | ltd-150-top* |
| rod-guide bore | Ø2 × 13 | 2 mm displacer rod | run | ltd-100-top-plate-* |
| rod-guide bore | Ø2 × 13 | 2 mm displacer rod | run | ltd-150-top-plate-* |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| Wikipedia | Stirling engine | web | CC BY-SA 4.0 (text) |
| James R. Senft | An Introduction to Low Temperature Differential Stirling Engines | book | Moriya Press verify |
| Long Earth Society | Engine builds | web, video | LES site |
Free files
★ Free files 2 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json
| ltd-100-top-plate-syringe | top plate Ø120 × 3: rod guide boss at x -5 (Ø2 bore, 13 long through plate and Ø20 boss), 10 mL syringe socket at x 40 (Ø15.9 from 8 to 20 above the underside, Ø10 port below so the Luer tip ends flush), 4 stand pads Ø9 × 4 with M3 tapped holes 6 deep, 6 × Ø3.4 on a Ø112 circle | STEP · STL |
| ltd-150-top-plate-syringe | top plate Ø170 × 3: rod guide boss at x -5 (Ø2 bore, 13 long through plate and Ø20 boss), 10 mL syringe socket at x 40 (Ø15.9 from 8 to 20 above the underside, Ø10 port below so the Luer tip ends flush), 4 stand pads Ø9 × 4 with M3 tapped holes 6 deep, 6 × Ø3.4 on a Ø162 circle | STEP · STL |
Plain text: sheet.txt · JSON: /api/geometry?object=ltd-top-plate
How it fits
Parts that fit it
Coat-hanger wire Ø2.0 mm and paper-clip wire Ø1.0 mm2 mm rod through the Ø2 bore in the top plate (run)
LTD crank stand for a 623 bearing, axis 112 above…2 × M3 down onto the top plate
Displacer rods Ø2 × 60, 78, 100 and 180, Ø3 ×…Ø2 rod in the top plate's Ø2 boreGoes in or on
LTD Stirling chamber ring, Ø100 and Ø150 × 206 × M3 on the Ø112 / Ø162 circleConnects to
LTD Stirling displacer Ø96 × 8 and Ø146 × 8the displacer's 2 mm rod runs in the Ø2 bore
Plastic syringes 1–60 mL as pistons and cylinders10 mL barrel in the Ø15.9 socket
Syringe pistonspower piston in that barrelAlso needed
Hobby brass tube, 1/16–21/32 in and 1–12 mm,…2 mm rodIn these build lists
LTD coffee-cup engineRuns on a cup of coffee: wide thin displacer, small piston.You might also need
Questions
How does the displacer rod pass through an LTD top plate?
Through a Ø2 bore straight through the plate and its Ø20 centre boss, 13 long, drawn at the 2 mm rod (fit: run).
What syringe fits the LTD top plate?
A 10 mL barrel (Ø15.9 OD) in the 12 mm deep socket; its Luer tip sits in the Ø10 port below and ends flush with the plate's underside.