i think I figured it out, i was setting my boundary as the upper part of the boundary box, when I set it to the bottom of the box it worked. thanks for the help

I want to have kids create a derby car profile, extrude and cnc. How could I cut this from the boundary box standard size and cut either side to side or circular. I tried to rough contour and it cuts too deep, I only want about .25 each pass. I know it will take longer but it is easier on bits. any help? see the sample image here web page