I'm interested in getting into the whole CNC scene, and got some ideas/drawings down on paper. Id like to mill precision model aircraft wings, each being about 7' in length. Considering how long I need the length to be, I was thinking about using belts and metal timing pulleys on the X and Y axis- but ran into a problem:

When using belts/pullys on the X and Y and a ball screw system on the Z, how does one ensure the same amount of movement per step on the Z, as well as the X and Y? Is there a formula or calculator somewhere, or can this be controlled via software? Do you know how other people who have overcome this problem?


Thanks for the help!