Artcam Feature problem

Hi Giys

right you know those twirly things on top of work vans that have fridges/air con that constantly turn around?

Im trying to make on for 1/76 scale model railway.

Now the way I drew it was a circle, and then another vector for the blades.

My plan was to machine the blades as a feature, and then cut out along the circle.

However I just cannot get the toolpath setup, I need to "rub" out the material not needed, but the best I can get is about 5 lines in mach3 or it will just cut along the vector and not actually machine it as a relief.

Where am I going wrong, how would you do it?

Thanks

DJH