For me it's just an availability thing, mild steel and stainless steel sheet is readily available. Don't even know if you can get spring steel in sheet.
Guilherme uses spring steel teeth on his drum.

Cheers Grant, being fan motors from a scrapped car I'm unsure what they'll draw. In their previous applications we didn't even blow 60a fuses but flicking a robot up may demand more.

Does anyone know if possible and how I can reverse the timing of fan motors? Currently advanced and want to mount them facing eachother.
I found this:
http://redneckrobots.com/ev/mod.htm

The motors 'look' similar, and I've read it a few times but it's just not sinking in :s