I tried to modify my servo but i don't have the right tools for it, so i just gave up on it. I'm building the $50 robot and am wondering where i can just buy a continous servo for cheap. I looked on servocity.com and the hs 311 servo with continous rotation is $29 just for one. Anyone know where I can buy cheap servos under $20 that rotate continously and is compatible with the $50 robot?