Screw machines are machine tools that use a number of cutting tools, fed into a rotating rod or bar, to make screws and other turned parts. A screw machine is a type of automatic turret lathe, that performs turning, lathing and cutting tasks to produce high-volume, low-cost parts.
Screw machines use long cylindrical rods as feed stock. The screw machinery turns the stock, faces and cuts the part, partitions it into an individual screw or part, and advances the rod to cut the next part. Screw machines can come configured as a simple screw machine with a single spindle or a machine with multiple spindles, typically four, six, or eight additional spindles. The multiple-spindle screw machine can perform facing, turning, drilling or boring, and cutting operations simultaneously. Both single and multiple spindle screw machines can be fitted with a number of attachments such as cross slides, countersinks, and burr and thread roll attachments, and provide increased throughput. A single spindle machine uses various cross slides that come into position to perform each operation in turn.
The feed stock used in screw machining can be made from a variety of metals, including carbon steel, stainless steel, copper, brass, aluminum, and many alloyed metals. A screw machine shop may specialize in a particular metal or even use plastic or polymeric compounds to create lightweight, corrosion-resistant plastic fasteners.
Screw machines are used to manufacture screws, fasteners, and other threaded components for a wide variety of uses, including automotive and appliance assembly, assembly of electronic components, use in heavy machinery, and to build medical and dental instruments. Screw machines are typically intensive to set up but once up and running can be easily monitored by a single operator.