I am going to build a CNC router. Although that's misleading since I don't nessecarily plan on actually using a router as the main tool. I want to see how precise I can get and what kind of quality I can achieve without spending lots of money. So I have some basic questions. The plans I've seen rely on a chain and sprocket to drive router. Their precision relies on the gear ratio between the linear motion of the gantry and the stepper motor, and the tightness of the chain and sprocket system. Even though the CNC I saw was able to mill PCB boards without any apparent defects, I think precision can be improved. I want to incorporate a location tracking system. I'm thinking an optical detector and black and white lines across the axises. But i'm open to suggestions, in fact it's why i'm here.