I come from China, I am a fan of your robot, in China, the market prospect of desktop manipulator is very big, I have been considering the lowest cost, using servo motor. Stepping motor is not as good as servo motor in robot application, so I found a cheap servo motor: integrated servo motor. Unfortunately, I have no way to modify the size of the body, I hope to give you the idea of using servo motor. The integrated servo motor is cheaper and requires less size of the control box.