This took some serious thinking and design work to get the two different modes of operation correct like the real thing. The unit has a push button that allows the lever to be pushed and pulled to any setting. If the push button is not used, then the micro-adjustment is selected by rotating the knob clockwise and anti-clockwise. 
 
At the back of the unit is a 10K ohm linear pot. This unit is designed specifically to fit into my C172 instrument panel, But I would imagine this will work for many applications. 
 
This unit does require hand tools such as a file and an M4 tap and die. 
 
The Build/Parts/Print guide can be found here:
 
https://www.737diysim.com/build-guides-1/c172-mix-lever