Ball screws and ball screw assemblies can be used for many functions. Common applications are as components of complex machinery. A lot of aeronautics mechanisms contain ball screws. Another application is in missile directional equipment and also for machines that manufacture scientific and medical instruments.

There are three important factors that apply to ball screws that make them invaluable for use in complex systems. They are linear actuators, which is critical. This means that they can change a turning energy into a straight line energy. The screw provides the turning energy, and is transferred into straight line movement which then causes the ball screw nut to move along the screw. This is a very important ability, which is required in such industries as robotics and construction.

Another important aspect of ball screw assemblies is that they do not suffer many frictional effects. As a result of this they have high levels of efficiency, because there is very little energy loss within the ball screw nut. Many ball screws have efficiencies of up to 90%, a very high level in comparison to other similar instruments.

A further factor which increases the usefulness of ball screws to certain industries is the degrees of precision they possess. Although this can vary depending on the design of ball screw in use, with rolled ball screws being less precise than precision ground ball screws. However, although it is more costly to purchase the ball screws with the greatest accuracy, these highly accurate ball screws are often crucial for some mechanisms.

Instrument ball screws can be exceptionally precise. A number of them are constructed to be accurate to 250 nanometres per centimetre. This level of accuracy is required by certain complex systems for example optical lens calibration instruments.