To model my machine, I prefer to start with some small components such as gears and base. The following videos are my screen recording, I want to record the entire modeling process so that I can know how to improve.

The problem that I get so far is to create an irregular shape of the model because I will be troubled by some mesh, lines and which polygon should I choose to start. As the video shows, I was struggling in modeling gears, in the beginning, i was thinking to create a gear that each section is disconnected, but after i saw the reference and all sections that need to be connected to each other.

In the video of the base modeling, I just used a sphere and cut it in half, after that I scale it a bit flat.

The following picture is all the modeling I have done so far. In the next stage, I will model the main shape of the machine and some more components.