As previously mentioned we wanted to make the spur gear ourselves. We can do this by laser cutting either wood or plexiglass based off a model in Solidworks. Making sure two gears mesh (interact) correctly can however be tricky as there is a lot of new terminology to understand. 

Below you can see the pinion gear that was purchased for the project. While having a small enough hub (center hole) we wanted as few teeth as possible. At a constant diameter fewer teeth would mean larger teeth which in turn would mean larger teeth could be cut on the spur gear. There is a set measurement for this called “diametral pitch” which is the number of teeth divided by the diameter of the pinion (green line) at which point will intersect with other gears.

Based on the packaging of our pinion gear we knew that the larger gear we were cutting had to also have a diametral pitch of 32. There are more variables that goes into the design of a gear to ensure meshing but because they are unknown to us we just have to try with the design we have. By using a gear generator online we got this: