GrblGru: How to build an Eggbot from plywood

Hello, everyone,

Easter is just around the corner,
and after I added the virtual 3D model of an EggBot to the program some time ago, I now want to provide a real model.
It was important for me to use the normal GRBL with 3 motors. The well-known variant with the servo for pen lifting was therefore eliminated.

Another important point was to keep costs as low as possible.
The practical execution is certainly not a mechanical engineering masterpiece.
Expectations of speed and precision must therefore not be set too high. It’s more about the principle.
However, the model is hopefully still suitable for teaching important knowledge of CNC technology in a playful way. (And you can also paint eggs with it)

Reproduction of the model is not only possible with GrblGru, but with any other control system.
If necessary, you can also saw out the plywood parts with a fretsaw.
The actual operation of the model is currently only tailored to GrblGru.
But maybe someone can change the construction so that a servo takes over the pen lift again.
This would also make it possible to control the whole thing with InkScape.

Suggestions for improvement are welcome.

Here are the costs for material and software:

Arduino UNO + CNC Shield 12 Euro
Stepper motors 3 x 2 Euro 6 Euro
Plywood 4mm 2 Euro
GRBL Software 0 Euro
GrblGru Software 0 Euro The latest version can be downloaded from my dropbox

Have fun with GrblGru

EggBotPage1.dxf (79.7 KB)
EggBotPage2.dxf (37.6 KB)


Thanks for the plans and of course software to make it happen!

@PhilJohnson Who needs a 3D printer to make an eggbot? :grin:

1 Like

The little machine is unfortunately very slow.
I think it’s quicker to paint the egg by hand.
But it’s fun watching its work. :slight_smile:

I just saw your eggbot thread and your video. Respect, there’s no way I can compete with that !!!
Your eggbot is of course the luxury variant. I only have the ‘poor man’ variation. :slight_smile:

However, I noticed that your swivel arm has no height adjustment.
Is it still possible to paint eggs and not just balls ?


That makes things easier, of course.
I will think about another second eggbot. But then with better motors and a servo arm. :slight_smile:


If I understand you correctly, you mean motives to draw them on the eggs.
Until now, I have only drawn my own motifs and saved them as DXF. But for Easter I am also looking for some new ideas. I’ll let you know when I find something nice.

I forgot to mention in my last post that the two attached DXf files were saved with metric units.
This means that they are 25.4 times larger than in imperial units.
That’s why I saved both drawings again with the factor 1/25.4.
I am not sure that the accuracy will be maintained. Please let me know if it doesn’t work.

EggBotPage1_Imperial.dxf (79.8 KB)

EggBotPage2_Imperial.dxf (38.3 KB)