Gear Ratio Model

Basic introduction to gears and gear ratios. This set of gears, crank, expandable base, and several spinners can be used to demonstrate the anatomy of a gear, how gears mesh, and visualize different gear ratios.

Print:

1 (or more) 11-hole base

2 (or more) feet [standard or expansion]

1 (or more) of each gear

1 crank

1 (or more) spinner

Special thanks to b2vn (and Randall Munroe!) for the excellent xkcd character models. For more nerd fun, go to: https://xkcd.com/

UPDATE 9/25

• Added expansion foot - this will allow you to connect as many bases as you'd like for even more gear fun! (Note: expansion feet won't interfere with each other, so go nuts.)
• Added more spinners, including an arrow to help demonstrate rotation/counter rotation of gears.
• Updated crank

Print Settings

Printer Brand:

Creality

Printer: 

Ender 3

Rafts:

Doesn't Matter

Supports: 

Yes

Resolution:

0.2 mm

Infill: 

10%

Filament: Any PLA Any

Notes:

All parts have ~0.2 mm tolerances, so a well-tuned printer capable successfully of printing mechanical parts will minimize post-processing.

If you experience fit issues, I recommend using the "horizontal expansion" feature in your slicer to shrink the pieces.

Post-Printing

Depending on your printer and settings, the gear and crank drive square may require light sanding.

The sockets in the base may also benefit from application of a lubricant.

How I Designed This

Gear Specifications

All gears:

Type = spur

Pressure angle = 20 deg

Module = 6.0

Backlash = 0.15 mm

Thickness = 5.0 mm

Each gear:

5 tooth | pitch diameter = 30

10 tooth | pitch diameter = 60

15 tooth | pitch diameter = 90

20 tooth | pitch diameter = 120

Category: Mechanical Toys