Ball Screws

A ball screw assembly is a mechanical device for translating rotational motion to linear motion. It consists of a precision ball screw and a ball nut packaged as an assembly with recirculating ball bearings. The interface between the ball screw and the nut is made by ball bearings, which roll in matching ball forms. As well as being able to apply or withstand high thrust loads, ball screws can do so with minimum internal friction. They are manufactured to close tolerances and are therefore suitable for use in situations in which high precision is necessary.


What sets Thomson ball screws apart?

Precision ball screws are not all alike. Whether it be metric ball screws, inch ball screws or miniature ball screws, key differences affect their performance and extend their lives. These include: 


Find your ideal ball screw solution in only a matter of minutes

We know you don’t have hours to spend researching and navigating part numbers to find the right ball screw for your design project. Thomson’s enhanced online product finder tool for ball screws simplifies the search and selection process, helping you quickly identify the right part, access pricing and lead times, and immediately purchase your final selections – all in one place.  

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Ball Screw Overview

How to Transfer a Ball Nut to a Ball Screw

How to Load Ball Bearings into an Inch Series Ball Nut

Identifying Your Ball Screw Assembly

How to Load Ball Bearings into a Metric Series Ball Nut

Ball Screws Training

Design and Theory

Ball screws convert rotary motion to linear motion and/or vice versa. A ball screw assembly consists of a screw and a nut with recirculating ball bearings. The connection between the screw and the nut is made by ball bearings, which roll in the matching ball forms in the screw and nut. The forces transmitted are distributed over a large number of ball bearings, giving a relatively low load per ball. Since ball screw assemblies use rolling elements, they have a low coefficient of friction. 

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Product Details

The Thomson ball screw product line consists of the following families:

  • Inch Rolled
  • Metric Rolled
  • Metric Precision Plus
  • Miniature Metric
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Installation Instructions

Do you need help transferring a ball nut to the screw? Mounting a ball screw assembly into your linear system or machine? Reloading ball bearings into a ball nut? Properly lubricating ball screws to achieve the rated life? Watch videos and view intuitive content on all of these topics.  


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When sizing a ball screw, there are three main performance areas to consider:

  • Life
  • Column loading or buckling
  • Critical speed
    • Screw
    • Nut
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