# Build list: LTD coffee-cup engine > What parts do I need to build a LTD coffee-cup engine? - Category: Stirling engines › Guide - Kind: List / guide - Basis: Every printed part is a free file on this site; bought items named with quantities - Page: https://xemstudio.com/objects/list-ltd-coffee-cup/ · JSON: https://xemstudio.com/api/geometry?object=list-ltd-coffee-cup · Plain text: https://xemstudio.com/objects/list-ltd-coffee-cup/sheet.txt - License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses ## Notes - Runs on a cup of coffee: wide thin displacer, tiny piston. - Numbers: Ø100 chamber · Ø96 × 8 foam displacer at 6 mm · 10 mL syringe at 5 mm · 1–3 Hz on 15–20 K ## Sizes | subsystem | object | parts | qty | print_or_buy | note | |---|---|---|---|---|---| | Plates | ltd-coffee-cup-engine-kit | ltd-100-bottom-plate-template, ltd-100-top-plate-syringe | 1 | buy | bottom plate in 2 mm aluminium | | Chamber | ltd-coffee-cup-engine-kit | ltd-100-chamber-ring-h16 | 1 | print | silicone seal | | Displacer | ltd-coffee-cup-engine-kit | ltd-100-displacer-foam-template | 1 | print | EVA foam | | Guide + rod | brass-tube-ks | brass-3mm, brass-2mm | 1 | buy | 3 mm tube guide (2.1 ID) pressed in the top plate; 2 mm rod | | Power piston | syringe-pistons | syringe-piston-10ml-f008 | 1 | print | replaces the plunger; lap into the barrel, run dry | | Syringe barrel | plastic-syringes | syringe-10ml | 1 | buy | barrel only, in the top plate socket | | Stands | ltd-coffee-cup-engine-kit | ltd-crank-stand-pair | 2 | print | | | Bearings | ball-bearings-metric | bearing-623 | 4 | buy | | | Crank | stirling-linkage-fittings | crank-disc-b3-stroke10 | 2 | print | Ø3 bore for the Ø3 shaft in the 623 stands; M3 grub | | Con-rods | ross-yoke-kit | conrod-45 | 2 | print | Ø3.2 plain ends; one to the piston fork, one to the displacer rod | | Pins | dowel-pins-metric | dowel-3x12 | 2 | buy | crank pin + piston pin | | Shaft | stirling-shafts-and-rods | crankshaft-3x80 | 1 | print | Ø3; steel drill rod for running | | Flywheel | nut-weighted-flywheels | flywheel-100-m8-b3 | 1 | print | Ø3 hub; start with 6 M8 nuts in alternate pockets, add until it carries | ## Where the files are - Long Earth Society: [Engine builds](https://longearthsociety.com/engineering/) — web, video — LES site ## Build order 1. Print ring, top plate, stands, templates; cut a 2 mm aluminium bottom plate from the template. 2. Foam displacer on a 2 mm rod through the 3 mm brass-tube guide. 3. Ring on the plates with silicone; syringe in the socket. 4. Crank stands, Ø5 shaft, tiny crank discs 90° apart; CD flywheel. 5. Set on a hot cup; flick the flywheel. All printed STLs: https://xemstudio.com/objects/list-ltd-coffee-cup/stl-list.txt ## Questions **What parts do I need to build a LTD coffee-cup engine?** 8 printed parts (all free here) and 5 bought items; see the table and build order on this page. **How do I download every STL for this build at once?** The stl-list.txt on this page lists every printed part's STL URL; paste it into a download script or your slicer's import. ## Fits with - [LTD (low-temperature differential, coffee-cup) Stirling kit: plates, chamber ring, displacer, top plate with syringe cylinder](https://xemstudio.com/objects/ltd-coffee-cup-engine-kit/) - [Hobby brass tube (K&S), 1/16–21/32 in and 1–12 mm, telescoping](https://xemstudio.com/objects/brass-tube-ks/) - [Syringe pistons: ring-less printed pistons with a con-rod fork for 10, 20 and 30 mL syringe barrels](https://xemstudio.com/objects/syringe-pistons/) - [Plastic syringes 1–60 mL as pistons and cylinders](https://xemstudio.com/objects/plastic-syringes/) - [Ball bearings, 683 to 6210 and flanged F6xx (ISO 15)](https://xemstudio.com/objects/ball-bearings-metric/) - [Stirling linkage fittings: rod clevises, shaft adapter, 625 crank stands, Ø3 crank discs, rhombic frame heads](https://xemstudio.com/objects/stirling-linkage-fittings/) - [Ross yoke kit (alpha Stirling with parallel cylinders)](https://xemstudio.com/objects/ross-yoke-kit/) - [Dowel pins, 2–6 mm (ISO 2338 / DIN 6325)](https://xemstudio.com/objects/dowel-pins-metric/) - [Stirling shafts and rods: Ø3 rods, Ø5 / Ø8 D-flat crankshafts, Ø5 tube rods, Ø3 pins, thrust spacers](https://xemstudio.com/objects/stirling-shafts-and-rods/) - [Nut-weighted flywheels: Ø100–200 with hex pockets for M8, M10, M12, 3/8 and 1/2 in nuts](https://xemstudio.com/objects/nut-weighted-flywheels/)