Hi GtsLabs
That type of work (your drawing) can be easily handled with a small mill, or an accurate router. The cutter diameter is the main concern. When you start using larger cutters, then you need greater machine mass for optimum operation.
That is a very deep slot to cut, with that diameter of tool. Typically, you could do it nicely with 8 passes, 1/8" deep. However, the deeper you go, the more difficult it is to get the chips out of the cut. They start going through the cutter again, and this roughens up the wall of the part. So, your best approach, since you seem to have extra material, may be to move the wedge profile inwards a bit, and mill a 5/16 wide groove, beginning with the 1/4" width, and then taking a cleanup pass around the walls on each side of your initial groove, just before you cut through.
Oh, you should bolt the wedge to something before it breaks free, at which point it would break your cutter off for you
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)