Newbie here. I have a problem and I don't know if is Mach3 or something else. When I go through the CAM process everything seems to be fine with the size but when I open the G-code it looks like it is the right size. After the job is finished it is only about half the size it is supposed to be according to the drawing that I made the G-code from. I have attached the first few lines of code of a project that I did last night.
It can only be that your steps per inch is not set correctly. It you tell the machine to move an axis 1 inch how far does it move. You need to test and calibrate if you have not done so already.