The most common answer you will get is with a timing belt. You could also use chains or gears. Theoretically you could use string or a cable but you would need a very large spindle to hold all the string you will need to have a predictable position.
![45-87-thickbox.jpg]( "45-87-thickbox.jpg")
Here is the QU-BD RPM. You can see that it uses one z-stepper but has 4 screws.
Here is the QU-BD RPM. You can see that it uses one z-stepper but has 4 screws.
