[Gui Cavalcanti]

In 2002, we used a combination of pillow block bearing supports for wheels and bushings for the gearboxes. The pillow blocks were nice because they self-centered and were easily attachable, but the bushings were easily 1/100th of the weight.

In 2003 we only used bronze bushings on the entire robot. It really kept our weight down in the drive train, and it's surprisingly low-friction. I think the key to using bushings is having an arbor press, precision hole creation capability (mill precision, not drill press and centerpunch precision), and a reamer to open the bushings after they've been pressed. It seems like a lot of work, but the payoff is size, weight, and cost savings that are very appreciable.

If you don't have precision capabilities, bushings are definitely out. Any misalignment between two pressed bushings supporting one shaft (we're talking .005"/ft here) can cause some serious friction problems.