Mini Mill Z axis CNC conversion

Two options to convert your mini mill's Z axis to CNC.

"Z final" is an adapter which allows you to direct drive the rack and pinion. There is not a lot of mechanical advantage here, and there is also quite a bit of backlash. But it is the quickest and easiest.

The other two prints combine to use a leadscrew drive which provides a fair bit of mechanical advantage over the rack and pinion (4:1 if you use an 8mm leadscrew). The top print centers the motor, the bottom print fits over the mill and holds the leadscrew nut. In addition you need a leadscrew, leadscrew nut, NEMA stepper and a coupler between the motor and the leadscrew (I turned this on a lathe). I also use a thrust bearing on the bottom to carry most of the load from the leadscrew as opposed to hanging from the stepper motor.

Blog post: http://harborfreightcnc.blogspot.com/2017/11/z-axis.html
X axis: https://www.thingiverse.com/thing:2586512
Y axis: https://www.thingiverse.com/thing:2591938

I know this entry is b