I have finalized the design of the wheel assembly since the proof of concept that I created to start with. I have gone through 3 different iterations of bogies to come up with the updated design. Most of the changes were made to find the proper way to keep the assembly together and prepare to connect it to the main chassis later on.
The updated model uses some hardware to keep it together. Since the road wheels and upstop are not easily able to be enclosed due to the capability of my 3D printer, I decided to use M1.6 bolts to secure an external cover to the main frame of the bogies.
I also noticed that the M3 bolt was not able to rotate easily with the friction from the tolerance of the PLA plastic that I was using. Because of this, I found an M3 Nylon insert that slides easily on the M3 bolt which will allow the bogie to rotate in pitch. This is small enough and cheap enough that I feel happy with it going into the final design. I would much rather have this insert over the possible vibration caused by making the hole too loose with the PLA alone.
The wheels are using paper clips as shafts for now. This is a cheap alternative for an axle and seems to work rather well. I have purchased bearings for the wheels with 1mm bore so until those arrive I won't be making any modifications to the wheel or the bogies. If I do come up with issues with them it will likely be due to using paper clips as shafts, but I will find 1mm wire or shafts if needed.
This image shows the proof of concept (left) and the updated model (right) in comparison to the size of a #2 pencil
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