How Do I Choose the Right Ball Screw?


If you just started tackling with linear motion, you could be in for a wild ride.

Ball screws are only one of the terms that could leave you confused, especially when you find out how many types of those there are.

In linear motion, just like in any other DIY framework, it is important to choose high-quality equipment, made of good materials that provide long-lasting high-precision results.

This endeavour doesn’t need to be costly, you just need a frame of reference for what to choose and how to choose it wisely.

In this article we are going to simplify the terms Linear Shafts and Ball Screw, all to bring you closer to the good decisions on your end.

What is a linear shaft and what do I need it for?


Linear shafts by Tuli provide a system that supports movement in a linear motion. They are straight, precision-machined bars which provide a surface on which linear bearings run to create that very system. Can be made of different materials, like aluminium, hardened steel, hardened stainless, composite materials or even plastic.

They are widely used to support or restrict loads that slide.

When there’s a need for a linear shaft, that means that you might be on the lookout for the proper ball screw!

What is a ball screw and what does it do?

A ball screw ( is a type of linear actuator because it converts the rotational motion of the shaft into a linear one. In some cases make the ball nut rotated and the linear shaft driven.

What to look for in a ball screw?


When looking for the right ball screw keep in mind the following characteristics:

  • the axial force required
  • axial clearance
  • axial load
  • lead accuracy
  • ball screw shelf life
  • the rotational speed of the nut
  • critical speed
  • and many others.

Ball screws can apply or resist heavy loads with minimum friction between the surfaces. They have been used successfully to eliminate friction between the nut and the screw all the while providing high-level efficiency and positioning accuracy.

Ball screw characteristics

They can achieve an efficiency of up to 96%, which is greater than the highest efficiency achieved with any other tool, such as a multi-start lead screw.

Other characteristics that emphasize the importance of a high-quality ball screw are:

  • high accelerations
  • higher trust loads
  • higher positioning accuracy
  • longer life of the screw system
  • reduced working temperatures that prevent overheating
  • reduced vibrations on screws
  • the high linear speed of the axis
  • larger system efficiency which results also in less wear.

The difference between a linear shaft and a ball screw


The ball screws mostly use a rotary transmitter mounted to the motor and linear motors use a magnetic linear scale (optical) that provide position feedback. The most accurate reading of an actual position is possible due to the linear scale which measures position at the load.

Choosing a high-quality shaft and ball screw will provide high-end results and keep the machines in tip-top shape no matter the circumstances that surround you.