A screw rod is a mechanical device for translating rotational motion to linear motion. A threaded shaft provides a spiral raceway for ball bearings which act as a precision screw.

As well as being able to apply or withstand high thrust loads they can do so with minimum internal friction.

The screw  rod  is also used as driving part on Machines of Metallurgy, textile, medical treatment, daily necessities and fields of space flight, aviation, military and automatic production lines.

The screw  rod is used as precision locating part in digit-control machine tools, precision lathe, measuring meter and devices. It offers prompt response, high locating accuracy, simple maintenance and long life.

They are made to close tolerances and are therefore suitable for use in situations in which high precision is necessary. The ball assembly acts as the nut while the threaded shaft is the screw.