Below is a list of Screw Machine Products manufacturers from Spring Grove, Illinois. Screw machine products include a wide range of parts formed by turning, a rotary machining process in which stock metal rods are threaded, drilled, slotted, milled, knurled and tapped into precision application parts. Screw machines may be mechanically operated by cams, or they may be controlled by fully automated CNC; both types of machines offer diverse capabilities, such as thread rolling and knurling.