Spirograph

Have fun by drawing with this Spirograph and the various gears! 

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The round gear guide has 84 teeth on the inside and 108 teeth on the outside. The linear gear guide has a width of a 24 teeth gear and a total of 54 teeth.

There are 6 gears and 2 guides which you can use for the drawing.

With Gear 14, 21, 28 and 42 (even ratios) you have to offset the teeth to get geometrical figures like in the picture. With Gear 53 and 76 (odd ratios) you can but don't have to offset the teeth after a finished rotation.

I recommend you to start with Gear 53 and 76. If you're a real spirograph enthusiast you can print the whole set.

In the guides you'll find tiny holes for pinning it down to your drawing board. Sometimes it gets quite difficult to not move the guide while moving the gear.

Updates

2022-09-19 // Added Gear 53 and Gear 76 (odd ratios)
2022-09-21 // Added Gear Triangle (now it get's wild!)

Ratios

Round gear guide inside : gears
 

• Gear 14
  Ratio 84:14 = 6
   
• Gear 21
  Ratio 84:24 = 4
   
• Gear 28
  Ratio 84:28 = 3
   
• Gear Triangle
  Ratio 84:30 = 2.8
   
• Gear 42
  Ratio 84:42 = 2
   
• Gear 53
  Ratio 84:53 = 1.585
   
• Gear 76
  Ratio 84:76 = 1.105

A visualisation of different ratios:
 

Feel free to contact if you have any ideas for adding elements to this collection.

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Printing

Printed on a Prusa mini+ 

Printing settings:
Recommended layer height: 0.2mm
Infill: 15-20%

Sanded the top layer to get rid of some blobs.

If you like this model, please post your makes of it right on Printables.

Filaments used:

• Polymaker PolyTerra Savannah Yellow
• Polymaker PolyTerraForest Green
• Polymaker PolyTerraLava Red

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If you're interested in the mathematics behind the drawing tool, I can recommend you this source:

[https://mathworld.wolfram.com/Hypocycloid.html](https://mathworld.wolfram.com/Hypocycloid.html)