How to use and measure with a micrometer in vr

Hello all:

I'm new to Unity, and have a project where I need to use a micrometer to measure objects in a vr environment. Attached is a pic of a micrometer.

WHAT I NEED:
1. use vive controllers to rotate the dials on the micrometer, which in turn moves the scale rod to clamp a object being measured.

2. when the object being measured is close to the gap in the micrometer, the object snaps to the micrometer so the user can measure the objects width by reading the numbers on the micrometer dial.

MY QUESTIONS:
1. I don't know how to implement this, so I'd appreciate providing the tools I need, what to learn, etc.
2. does my movable parts in the micrometer 3d model need to be separate, then grouped as a child null object?
3. How to make the micrometer dials rotate, but still stay attached to the whole micrometer if the user moves the entire model.

Based on my research, I plan on using SteamVR plugin. I will make my vive controller buttons rotate the micrometer dials. One controller picks up the micrometer tool, then the other controller rotates the dials.

I don't know how to approach this, so all help will be appreciated!
Thanks!!!

 

Interesting,please let me know if you're able to do it now.
Thankyou,