I think within the next century and a half, micro robotic "bugs" will take over the machining industry. Little ant-sized machines with cutting tools will swarm over a solid workpiece, and with radar-like positioning technology, they will know where to cut.
This will enable cool things like reverse tapered holes... bigger in the inside, smaller at the surface. Welding can be done microscopically such that there won't even be a weld bead.
Government control over the production and use of these devices will be mandatory as to prevent evil warlords from using them against people.