i want to make my own cnc machine from scratch because its cheaper to make then buy a premade one. I noticed that some machines go for tens of thousands of dollars and I cannot understand how they can cost that much to build. I am not afraid to learn what I need to learn to make one. I can do basic arduino programming and stuff. I understand the concept of G-Code, its not that hard. The thing I cannot understand is how do you go from G-Code to moving the stepper motors. How does a controller translate a move x 20 units to moving the stepper x amount of steps and keep dimensional accuracy? If the CAD g-code says move 200mm in x direction, how to you translate the g code to tell the stepper motor that 200mm? any help is greatly appreciated. IF you need clarification please ask in the comments.