DIY Eggbot for 15$

Hi guys!

I'd love to share my new work — Eggbot!

Eggbot is a device that draws with a usual marker or felt-tip pen on eggs and any other spherical objects - pin-pong balls or light bulbs.

My Eggbot turned out to be a budget because I tried to use the most affordable parts. Unlike most other projects, I used 28BYJ-48-12V stepper motors, which together with the driver for aliexpress cost only $ 2.

Here is a complete list of non-printed components that I needed in the project:
1 x Arduino UNO
2 x 28BYJ-48-12V Stepper Motor
2 x ULN2003 Stepper Motor Driver
1 x SG90 Micro Servo Motor
1 x 12V power supply
1 x USB Cable for connecting to a computer
2 x 608 Bearing
Some wires

I also needed various bolts and nuts, which can be easily found in any hardware store:
1 x 15x20mm Spring
1 x 2x18mm Nail without a cap
2 x M4x16 Bolt
2 x M4 Nut
8 x M3x12 Screw
5 x M3x16 Screw
12 x M3 Nut
4 x M3 Washer
12 x M2x4 Screw
24mm rubber gasket (can be printed if there is Flex plastic)
15mm rubber gasket (can be printed if there is Flex plastic)

What do you think about this project?

What drawing package did you use for the exploding parts diagram ?

How much of this (mechanical) design was premediated (ie carefull design in some drawing/visualiztion program) as opposed to trial and error (a wastebin full of parts that are too small/large or will notdo the job right?)?

But otherwise - it looks really really neat!