# Build list: Gamma Stirling, 2 in tri-clamp

> What parts do I need to build a Gamma Stirling, 2 in tri-clamp?

- 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-gamma-2in-tri-clamp/ · JSON: https://xemstudio.com/api/geometry?object=list-gamma-2in-tri-clamp · Plain text: https://xemstudio.com/objects/list-gamma-2in-tri-clamp/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses

## Notes

- The Long Earth Society engine: hot spool, shell displacer, graphite or syringe piston, counterweighted crank, Ø100 flywheel.
- Numbers: Ø46 × 90 displacer at 20 mm stroke · Ø20 piston at 12 mm · ratio ~9 · 200–500 rpm on a tea light · 0.1–0.5 W

## Sizes

| subsystem | object | parts | qty | print_or_buy | note |
|---|---|---|---|---|---|
| Hot end | tri-clamp-end-cap | tc-cap-2in-flat | 1 | print | flame side |
| Cylinder | tri-clamp-spool | tc-spool-2in-6in | 1 | buy | buy the stainless spool; print to check |
| Joints | tri-clamp-end-cap | tc-gasket-2in | 2 | buy | ISO 2852 Type B gaskets on the cold joints |
| Clamps | tri-clamp-clamps | clamp-half-2in | 4 | print | two halves per joint; stainless clamp at the flame side |
| Hot joint | tri-clamp-clamps | hot-gasket-template-2in, heat-shield-2in | 1 | print | trace on 0.5 mm graphite / mica sheet for the flame-side joint |
| Displacer | tri-clamp-displacers-and-heads | displacer-shell-2in-90, displacer-cap-2in | 1 | print | 0.75 mm gap, 20 mm stroke |
| Regenerator | regenerator-and-heat-materials | regenerator-cage-47-5x40 | 1 | print | pack with #100 stainless mesh |
| Displacer rod | stirling-shafts-and-rods | rod-3x150 | 1 | print | cut to length; Ø3 music wire or drill rod for a running engine (it slides) |
| Rod guide | brass-tube-ks | brass-4mm | 1 | buy | K&S 4 mm brass (3.1 ID) for the Ø3 rod; press in the head, 20–30 mm proud |
| Cold head | tri-clamp-displacers-and-heads | head-displacer-2in | 1 | print | guide bore + 4 mm barb; or head-crank-2in |
| Transfer | silicone-tube-and-fittings | silicone-tube-4x6-50, barb-4mm | 1 | print | keep under 30 mm |
| Power cylinder | power-cylinder-piston-crosshead | liner-20x45-flanged, piston-20x18-blank | 1 | print | lap to fit, or graphite piston in a Ø20 glass tube, or syringe-10ml |
| Crosshead | power-cylinder-piston-crosshead | crosshead-8mm-rod3, crosshead-guide-8mm, wrist-pin-3x16 | 1 | print | recommended with a lapped piston |
| Base plate | gamma-base-plate-and-beam | base-plate-2in | 1 | print | 4 × M5 to 2020 or a board |
| Crank stands | stirling-linkage-fittings | crank-stand-625-h60 | 2 | print | 625 pockets for the Ø5 crankshaft; slotted feet match the base plate |
| Bearings | ball-bearings-metric | bearing-623, bearing-625 | 6 | buy | 4 × 623 in the con-rods, 2 × 625 on the shaft |
| Crankshaft | stirling-shafts-and-rods | crankshaft-5x100-dflat | 1 | print | print flat side down, 100 % infill; or Ø5 steel |
| Spacers | stirling-shafts-and-rods | spacer-5mm-t1, spacer-5mm-t2 | 4 | print | set the 1 mm gaps along the crankshaft |
| Crank discs | counterweighted-cranks | cw-crank-disc-stroke20, cw-crank-disc-stroke15 | 2 | print | 90° apart, displacer leads |
| Crank pins | dowel-pins-metric | dowel-3x12 | 2 | buy | press fit |
| Rod clevis | stirling-linkage-fittings | rod-clevis-3mm | 1 | print | grub on the Ø3 displacer rod; conrod-50's 623 end on its Ø3 pin |
| Con-rods | crank-conrod-flywheel-kit | conrod-50, conrod-40 | 2 | print | 50 displacer, 40 piston |
| Flywheel | nut-weighted-flywheels | flywheel-150-m10-b5 | 1 | print | press in 18 M10 nuts (or fewer) |
| Flywheel nuts | hex-nuts-metric |  | 18 | buy | 18 × M10 hex nuts (ISO 4032: 16 AF × 8.4), or 12 × M12 / 1/2 in on the Ø150 M12 wheel |
| Collars / clips | shaft-collars-clips-and-shafts | collar-5mm | 2 | buy | locate the crankshaft |
| Fasteners | socket-head-cap-screws-metric | shcs-m3x8, shcs-m3x10, shcs-m3x16 | 20 | buy | + M3 nuts, M5 × 10 button heads, inserts |
| Heat | tea-light-candles | tea-light-38x16 | 1 | buy | 15–20 mm below the cap |
| Instruments | instrument-mounts | probe-clamp-k-type-3mm, probe-clamp-ds18b20-6mm, hall-sensor-mount-to92 | 3 | print | optional |
| Calibrate first | printer-calibration-coupons | hole-gauge-m3-2-8-to-3-6, pin-gauge-2-8-to-3-2, bearing-pocket-gauge-623-625-608 | 1 | print | once per printer |

## Where the files are

- Long Earth Society: [Engine builds](https://longearthsociety.com/engineering/) — web, video — LES site

## Build order

1. Print the calibration coupons and set your slicer offsets.
2. Print displacer, cap, heads, crank discs, con-rods, flywheel, stands, base plate, liner (or buy a glass tube + graphite piston).
3. Buy: spool, two clamps + gaskets, six bearings, M3/M5 screws, 4 mm K&S brass tube (rod guide), #100 mesh, 4 mm silicone tube, tea light.
4. Assemble displacer on its rod; press the cap; rod through the guide in the cold head.
5. Clamp spool between hot cap and cold head with the regenerator cage in the gap.
6. Base plate on 2020; stands and crankshaft on the plate; crank discs 90° apart, displacer leading.
7. Con-rods to the rod and the piston (crosshead if lapped); flywheel with the counterweight arc opposite the heavier pin.
8. Transfer tube to the power cylinder; tea light 15–20 mm under the hot cap; turn the flywheel to start.

All printed STLs: https://xemstudio.com/objects/list-gamma-2in-tri-clamp/stl-list.txt

## Questions

**What parts do I need to build a Gamma Stirling, 2 in tri-clamp?**

33 printed parts (all free here) and 9 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

- [Tri-clamp end cap and gasket, 1.5 and 2 inch](https://xemstudio.com/objects/tri-clamp-end-cap/)
- [Tri-clamp spool (two ferrules on a tube), 1.5 and 2 inch](https://xemstudio.com/objects/tri-clamp-spool/)
- [Tri-clamp clamps (printable two-bolt), hot-joint gaskets and heat shields: 1.5, 2 and 3 in](https://xemstudio.com/objects/tri-clamp-clamps/)
- [Tri-clamp displacers and engine heads: 1.5, 2 and 3 in spools](https://xemstudio.com/objects/tri-clamp-displacers-and-heads/)
- [Regenerator and heat materials: stainless mesh counts, steel wool, scrubbers, mica, fiberglass, ceramic, firebrick](https://xemstudio.com/objects/regenerator-and-heat-materials/)
- [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/)
- [Hobby brass tube (K&S), 1/16–21/32 in and 1–12 mm, telescoping](https://xemstudio.com/objects/brass-tube-ks/)
- [Silicone and PU tube, hose barbs and push-fit fittings (the transfer port)](https://xemstudio.com/objects/silicone-tube-and-fittings/)
- [Power cylinder liners, piston blanks, crosshead and guide (the non-syringe power piston)](https://xemstudio.com/objects/power-cylinder-piston-crosshead/)
- [Gamma frame: base plates for tri-clamp engines, rocker beam and pivot post](https://xemstudio.com/objects/gamma-base-plate-and-beam/)
- [Stirling linkage fittings: rod clevises, shaft adapter, 625 crank stands, Ø3 crank discs, rhombic frame heads](https://xemstudio.com/objects/stirling-linkage-fittings/)
- [Ball bearings, 683 to 6210 and flanged F6xx (ISO 15)](https://xemstudio.com/objects/ball-bearings-metric/)