# Con-rods with Ø3 pin ends, 45 and 60 mm, 8 × 5

> What size con-rod connects a syringe piston to a crank?

- Category: Stirling engines › Drives & mechanisms
- Kind: Hardware
- Basis: Centres from the solved linkages (Ross yoke 60, alpha V-twin 60, can / LTD 45); Ø3 ends at the Ø3 pins; 5 thick for the syringe piston's 5 mm fork
- Page: https://xemstudio.com/objects/pin-end-con-rods/ · JSON: https://xemstudio.com/api/geometry?object=pin-end-con-rods · Plain text: https://xemstudio.com/objects/pin-end-con-rods/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses

**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.

## Notes

- Plain con-rods whose Ø3 end holes turn on Ø3 pins (fit: run). All are 5 thick, the width of the syringe piston's fork slot, with 8 mm wide ends.
- Conrod-45: 45 mm centres, 53 × 8 × 5, for the can and coffee-cup engines.
- Conrod-60: 60 mm centres, 68 × 8 × 5, yoke corner to piston on the Ross yoke alpha.
- Alpha-conrod-60: 60 mm centres on Ø8 ends joined by a 6 wide web, for the alpha V-twin, where both rods share one crank pin and keep 0.8 mm from the syringe barrel wall over a full turn.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| con-rod ends | Ø3 | Ø3 pins (turn on them) | run | alpha-conrod-* |
| con-rod ends | Ø3 | Ø3 pins (turn on them) | run | conrod-* |

## Sizes

| file | centres | length | end width | thickness | holes | used on |
|---|---|---|---|---|---|---|
| conrod-45 | 45 | 53 | 8 | 5 | Ø3 | can engine, LTD engine |
| conrod-60 | 60 | 68 | 8 | 5 | Ø3 | Ross yoke alpha |
| alpha-conrod-60 | 60 | 68 | 8 | 5 | Ø3 | alpha V-twin |

## Where the files are

- Wikipedia: [Ross yoke](https://en.wikipedia.org/wiki/Ross_yoke) — web — CC BY-SA 4.0 (text)
- Long Earth Society: [Engine builds](https://longearthsociety.com/engineering/) — web, video — LES site

## Free STEP/STL (3 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/pin-end-con-rods/index.json

- conrod-60: [STEP](https://xemstudio.com/files/hardware/ross-yoke-kit/conrod-60.step) · [STL](https://xemstudio.com/files/hardware/ross-yoke-kit/conrod-60.stl) — con-rod 60 mm, 8 wide × 5, Ø3 ends (pins turn in them): yoke corner to the syringe piston's fork
- conrod-45: [STEP](https://xemstudio.com/files/hardware/ross-yoke-kit/conrod-45.step) · [STL](https://xemstudio.com/files/hardware/ross-yoke-kit/conrod-45.stl) — con-rod 45 mm, Ø3 running ends, 8 wide × 5: plain-end rod for the can and coffee-cup engines' syringe pistons
- alpha-conrod-60: [STEP](https://xemstudio.com/files/hardware/alpha-v-twin-frame/alpha-conrod-60.step) · [STL](https://xemstudio.com/files/hardware/alpha-v-twin-frame/alpha-conrod-60.stl) — con-rod 60 mm, 8 wide × 5, Ø3 plain ends (the pins turn in them; make two): small end in the syringe piston's 5 mm fork

## How it fits

### Connects to
- [Syringe pistons: ring-less pistons with a con-rod fork for 10, 20 and 30 mL syringe barrels](https://xemstudio.com/objects/syringe-pistons/): small end in the piston's 5 mm fork on a Ø3 pin
- [Ross yoke a = h = 20 for two parallel syringes](https://xemstudio.com/objects/ross-yoke/): conrod-60 on the yoke's corner pins
- [Alpha V-twin crank disc Ø26, one pin, 16 mm stroke](https://xemstudio.com/objects/alpha-v-twin-crank-disc/): both alpha-conrod-60s on the one Ø3 crank pin
- [Rod clevises for a Ø2 or Ø3 rod or a Ø5 tube, 5 mm gap](https://xemstudio.com/objects/rod-clevises/): conrod-45 on the Ø3-bore crank discs

### Alternatives
- [Crank discs for a Ø5 shaft, 10 to 30 mm stroke](https://xemstudio.com/objects/crank-discs-5mm-bore/): con-rods with 623 bearing ends

### Also needed
- [Dowel pins, 2–6 mm (ISO 2338 / DIN 6325)](https://xemstudio.com/objects/dowel-pins-metric/): Ø3 pins

## Questions

**Why is the alpha V-twin con-rod 60 mm long?**

A shorter rod swings further and touches the 14.5 mm barrel near its mouth; at 60 mm and 16 mm stroke it clears the wall by about 0.8 mm.

**How thick are these con-rods?**

5 mm, the width of the 10 mL syringe piston's fork slot.

**What pins do the con-rods use?**

Ø3 pins; the rod ends turn on them.

## Fits with

- [Syringe pistons: ring-less pistons with a con-rod fork for 10, 20 and 30 mL syringe barrels](https://xemstudio.com/objects/syringe-pistons/)
- [Ross yoke a = h = 20 for two parallel syringes](https://xemstudio.com/objects/ross-yoke/)
- [Alpha V-twin crank disc Ø26, one pin, 16 mm stroke](https://xemstudio.com/objects/alpha-v-twin-crank-disc/)
- [Can-engine diaphragm: membrane, clamp rings and centre disc, Ø40 / 50 / 60](https://xemstudio.com/objects/can-engine-diaphragm/)
- [Crank discs for a Ø5 shaft, 10 to 30 mm stroke](https://xemstudio.com/objects/crank-discs-5mm-bore/)