Rover

The base was cut from 6mm medium density fibre board (MDF) with a dremel and cutting bit. I made a jig with pieces of scrap timber to ensure that the cuts were accurate and smooth, and I cut all three decks at the same time. (The robot only has one deck so far.)

The wheels are small trolley wheels that I bought for a few dollars from the hardware store, however I sculpted and smoothed the centres with the dremel and a grinding wheel to get the clean lines. The unmodified wheels had radiating ridges which would have prevented them from being mounted on those hubs.

Another of my robots called "Ally" uses a larger type of trolley wheel which can be clearly seen in this photo on my home page where I used to post my robot projects http://asmith.id.au/ally-base.html

For the time being I am using the store bought ones, however they are not without problems too.

The grub screws that came with them would not hold them on the shaft securely, even when glued, and I had to use 1/2" 4-40 screws which stand proud of the hub and risk getting caught on something as they turn.

Finding 4-40 screws is also a big problem if you happen to live somewhere that uses metric (i.e. almost everywhere).

I don't consider this to be a solved problem yet. I won't be buying any more hubs, but I'm not satisfied with the home made varieties either. The subject warrants further research and development.