I cut the cogs from chopping board, it's great stuff!
I drilled a daisy pattern in the board and then pushed out the middle, which formed a rather handy cog. I sandwiched four of them together with a bearing in the middle to make each gear.
The motors and planetary gearbox come from ultra cheap Tesco 9.6v drills, it's basically a complete unit in itself, just stick a gear on it and you're good to go. They're powered by a Novak M2 Dig speed controller which is more than it needs but I might put larger motors in later on. I really can't overstate how good chopping board is for prototyping, it's strong for its weight, easy to cut, you can even heat and reform it. Oh, and it's cheap too! ;-)
( JamHamster My eyes, my beautiful eyes!, Sun 20 Nov 2011, 20:00, 1 reply)

Fantastic
So, and sorry to keep asking questions, did you cut everything that is white from the chopping board? The stuff in between the tracks I mean. What are the tracks made from?
(dchurch bah, Mon 21 Nov 2011, 11:44, closed)

No worries!
Everything that's white is chopping board and the tracks are made from bike chain and aluminium pipe bolted together at every other chain link. ;-)
( JamHamster My eyes, my beautiful eyes!, Mon 21 Nov 2011, 12:53, closed)