US Patent 9969009 Method for producing contoured holes

A method for manufacturing a contoured hole, the hole being manufactured in a wall, the wall comprising a first, a second surface, and a wall thickness between the wall first and second surface. The comprises manufacturing a first non-penetrating hole extending from the first surface and into the wall, wherein a distal end of the first hole is located within the wall such that the first hole does not penetrate the wall second surface, and manufacturing a through hole, wherein the through hole is fluidly connected with first hole and penetrates the wall second surface.