I'm making a rod height adjustment knob, the rod has a round profile at the end and inserted into the adjustment knob, when the knob is rotated the rod will ride up and down the cut out profile. I Need help with creating a cut feature on a cylindrical part where a round/ball endmill moves in and out at various depths as the part is rotated.

I created a sketch and projected on the surface but can't seem to get a cut feature that rotate along the radius and varying depth. Basically I want the round endmill profile to move along the radius of the part with a varying depth profile, any ideas?