mounting the component in a drilling machine, the component having a target region at which the hole is to be drilled, and the component and a jet head being situated relative to each other in a drilling arrangement in which the target region is at a first position that is vertically equal to or vertically above a second position at which the jet head is located;

jetting a liquid stream from the jet head, the liquid stream containing either abrasive particles or a laser beam, the liquid stream impinging the target region, the abrasive particles or the laser beam causing removal of material from the component at the target region to form the hole in the component, the liquid stream rebounding off of the component as back-splash liquid, and the drilling arrangement causing gravitational draining of the back-splash liquid from the hole to reduce interference between the back-splash liquid in the hole and the liquid stream; and

providing a computerized 3-dimensional model of the hole that is to be drilled, dividing the model into a series of successive 2-dimensional layers, and relative to the component moving the jet head such that the liquid stream moves across the target region layer-by-layer of the series of successive 2-dimensional layers and such that the liquid stream moves across the target region in a series of spiral patterns layer-by-layer of the series of successive 2-dimensional layers such that the abrasive particles or the laser beam causes removal of the material layer-by-layer, wherein the spiral patterns alternate layer-by-layer between inside-out movement of the jet head and outside-in movement of the jet head.