I worked on my first design from January 2022 to March 2022, learning FreeCad from this amazing channel and applying what I learned to my first design. 

I did a few iterations that are shown in the picture below to find:

1. Thread compatible with the hydro-flask (I did a few iterations to get a working thread)
2. Design that fits inside the soda stream
   • The first iteration couldn't fit because the top part wasn't long enough
3. Thread compatible with the soda stream
   • The soda stream I have doesn't use the thread. It uses the larger
     base layer (yellow arrow) to attach to the soda stream bottle and form a sealed link. In the mean time, I improved the visual look of the design.

In the end, I was able to design a working adapter. However, I realized quickly that the interface between the adapter and the hydro-flask needed to be fully sealed to avoid any spill.

From this point, the project was toss away until December 2022 to focus on other projects.