Rotation rigging and parents

[Joe232 (Joe Smith)]

I am trying to do this where if I rotate the parent bone, it will rotate the entire cube and the knob and the knob’s position remains the same, just the rotation changes. I parented the object to the bones with empty weights and I manually selected the parent bone to affect just the cube and the knob is affected by the child bone. Why is it that the main cube does not rotate in the center if I rotate the parent bone?

Also my other issue is how do i set the child bone to rotate if I rotate the parent bone?

[Joe232 (Joe Smith)]

I had to post the bone right in the center in order to move the box in the middle and there is no need for a child bone for the knob as it will move on its own.