I want to cut out a compound bow riser out of fiberglass. I am confused as to how to do it. My starter material is not flat. It has a 2 inch rise in the center. I have an example in a picture. Is it possible to cut material that is not uniform?
yes you can cut it. you may need to make a fixture to hold it you will need a long enough cutter to reach the bottom without the collet hitting the top. for longer bits, thicker is better so it does not bend (as much). so, select the largest diameter cutter that is smaller than your curves. do at least one roughing pass and a finishing pass to reduce the effects of the long tool chattering. expect the cutter to be blunt after this (-: fiberglass is nasty to cutters.