I didnt use an endmill. I just drilled a hole in the surface (not all the way through) larger than what I wanted the dimple size to be. I filled the hole woth bondo, and before it cured i pushed a large glass marble into the bondo. When it cured, I removed the marble and was left with a perfect smooth dimple. I then block sanded the surface of the handle to remove the extra bondo that pushed out around the marble and was done.