It was very simple. First I used a mouldable paste to glue a 4mm bushing on each shaft of the gear box, then I screwed the wheel and a cap to it. I built the base with pieces of ABS plastic which is very strong and easy to shape like wood. Yesterday I went to shot some footages for a client and...
Well, thanks to this thread I finally made my DIY follow focus. I didn't use the BaneBots wheels but a simple one I bought in a hardware store for € 1,00 and to improve the grip I applied a tape used on the handle of the tennis racquets. It's working very good even if there is a little backlash...