# Crank webs (bar cranks), Ø5 bore, 10 to 30 mm stroke

> What is a crank web and how do two make a crankshaft throw?

- Category: Stirling engines › Drives & mechanisms
- Kind: Hardware
- Basis: Bar crank 6 thick with a Ø22 × 12 hub, Ø5 bore, Ø3 pin at stroke / 2 and a counter-mass lobe
- Page: https://xemstudio.com/objects/crank-webs-5mm-bore/ · JSON: https://xemstudio.com/api/geometry?object=crank-webs-5mm-bore · Plain text: https://xemstudio.com/objects/crank-webs-5mm-bore/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

- A 14 mm wide bar 6 thick with a Ø3 pin hole at half the stroke, a Ø18 counter-mass lobe centred 6 mm behind the axis, and a Ø22 hub 12 tall with a Ø5 bore.
- A radial Ø2.5 hole (M3 tap drill) 9 mm up the hub locks it to the shaft.
- Two webs and a Ø3 pin make a throw in the middle of a shaft, so the con-rod sits between two bearings.
- Overall length 27, 29.5, 32, 34.5, 37 for 10–30 mm stroke; 22 wide.

## 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 |
|---|---|---|---|---|
| web bore | Ø5 | Ø5 crankshaft (M3 grub) | slide | crank-web-* |
| web pin hole | Ø3 | Ø3 crank pin | press | crank-web-* |
| web grub hole | Ø2.5 | M3 tap drill | designed | crank-web-* |

## Sizes

| file | stroke | pin offset | overall | hub |
|---|---|---|---|---|
| crank-web-stroke10 | 10 | 5.0 | 27 × 22 × 12 | Ø22 × 12 |
| crank-web-stroke15 | 15 | 7.5 | 29.5 × 22 × 12 | Ø22 × 12 |
| crank-web-stroke20 | 20 | 10.0 | 32 × 22 × 12 | Ø22 × 12 |
| crank-web-stroke25 | 25 | 12.5 | 34.5 × 22 × 12 | Ø22 × 12 |
| crank-web-stroke30 | 30 | 15.0 | 37 × 22 × 12 | Ø22 × 12 |

## Where the files are

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

## Free STEP/STL (5 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/crank-webs-5mm-bore/index.json

- crank-web-stroke10: [STEP](https://xemstudio.com/files/hardware/counterweighted-cranks/crank-web-stroke10.step) · [STL](https://xemstudio.com/files/hardware/counterweighted-cranks/crank-web-stroke10.stl) — crank web (bar crank) 10 mm stroke, Ø5 bore with set-screw hub, Ø3 pin; two make a full crankshaft throw
- crank-web-stroke15: [STEP](https://xemstudio.com/files/hardware/counterweighted-cranks/crank-web-stroke15.step) · [STL](https://xemstudio.com/files/hardware/counterweighted-cranks/crank-web-stroke15.stl) — crank web (bar crank) 15 mm stroke, Ø5 bore with set-screw hub, Ø3 pin; two make a full crankshaft throw
- crank-web-stroke20: [STEP](https://xemstudio.com/files/hardware/counterweighted-cranks/crank-web-stroke20.step) · [STL](https://xemstudio.com/files/hardware/counterweighted-cranks/crank-web-stroke20.stl) — crank web (bar crank) 20 mm stroke, Ø5 bore with set-screw hub, Ø3 pin; two make a full crankshaft throw
- crank-web-stroke25: [STEP](https://xemstudio.com/files/hardware/counterweighted-cranks/crank-web-stroke25.step) · [STL](https://xemstudio.com/files/hardware/counterweighted-cranks/crank-web-stroke25.stl) — crank web (bar crank) 25 mm stroke, Ø5 bore with set-screw hub, Ø3 pin; two make a full crankshaft throw
- crank-web-stroke30: [STEP](https://xemstudio.com/files/hardware/counterweighted-cranks/crank-web-stroke30.step) · [STL](https://xemstudio.com/files/hardware/counterweighted-cranks/crank-web-stroke30.stl) — crank web (bar crank) 30 mm stroke, Ø5 bore with set-screw hub, Ø3 pin; two make a full crankshaft throw

## How it fits

### Goes in or on
- [Crankshafts Ø3, Ø5 and Ø8 with full-length D-flat](https://xemstudio.com/objects/stirling-crankshafts/): Ø5 bore, M3 grub

### Connects to
- [Connecting rods 30 to 80 mm centres with 623 pockets](https://xemstudio.com/objects/connecting-rods-623/): 623 on the pin between the webs

### Also needed
- [Crank and wrist pins Ø3 × 12, 16, 19, 20 and 23](https://xemstudio.com/objects/pins-3mm/): Ø3 pin between two webs

## Questions

**Disc crank or crank web?**

A disc is one part with the con-rod outboard. Two webs make a centre throw so the con-rod runs between two bearings: stiffer, for two-cylinder or beam engines.

**What pin joins two crank webs?**

A Ø3 pin through both pin holes; the con-rod's 623 turns on it between the webs.

## Fits with

- [Counterweighted crank discs, Ø5 bore, 10 to 30 mm stroke](https://xemstudio.com/objects/counterweighted-crank-discs/)
- [Crank and wrist pins Ø3 × 12, 16, 19, 20 and 23](https://xemstudio.com/objects/pins-3mm/)
- [Connecting rods 30 to 80 mm centres with 623 pockets](https://xemstudio.com/objects/connecting-rods-623/)
- [Crankshafts Ø3, Ø5 and Ø8 with full-length D-flat](https://xemstudio.com/objects/stirling-crankshafts/)