Bearing Shafts

Thomson RoundRail shafting is manufactured to the highest quality standards in an ISO 9001:2015 registered facility to provide industry leading case hardness and depth, surface finish, roundness, straightness and cylindricity. Thomson offers the widest selection of bearing shafts in the industry to ensure optimal performance, minimal maintenance and long life.

Why choose Thomson bearing shafts?

For more than 70 years, Thomson has been producing precision linear shafting for its Linear Ball Bushing® Bearings and other applications.

  • We are one of a few linear motion component suppliers producing their own bearing shafts.
  • We offer the largest selection of linear shafting – not just the popular sizes.
  • We offer a complete linear motion solution – not just one component of a linear system.
  • We offer the widest range of inch and metric bearing shafts, support rails and support blocks in the market today.
  • We continually optimize our processes to ensure optimal bearing performance and extended life.
  • We perform thousands of hours of laboratory testing per year to continually evaluate our products.

While bearing shafts may appear the same to the untrained eye on the surface, there are significant performance differences due to the manufacturer’s selected standards and the manufacturing processes used to achieve them. Our most popular shafting, Thomson 60 Case®, was developed and is continually enhanced because of our goal to provide an optimal inner race surface for the high demands of linear bearings. To accomplish this, we focus on offering a consistent finish, roundness, straightness, cylindricity, case hardness and depth on all shafting. Unlike common bearing shafts, Thomson 60 Case LinearRace® shafts are manufactured to the highest quality standards in an ISO 9001:2015 registered facility. Our techniques have been continuously upgraded with proprietary knowledge gained from decades of manufacturing experience. Using Thomson 60 Case with Thomson Linear Ball Bushing Bearings ensures optimal bearing performance and travel life.

In order for Thomson bearing shafts to be used as linear guides, they must be properly mounted. Thomson offers a full selection of shaft supports to simplify this process.

  • Continuously supported shafts are attached and supported along its entire length. This configuration is used when loads are high or more rigidity is desired. They require open bushings or re-circular linear roller bearings to be used as the support would be in the way of a closed linear bearing.
  • End supported shafts are supported at both ends with the middle of the shaft clear of the mounting surface. This configuration is used when the loads are light or deflection from the shaft is acceptable. In end supported applications, closed bushings are used since the middle of the shaft is clear of obstructions.


Square vs. Round: Which Linear Guide is Best for Your Application?

When specifying linear guides for your applications, there are two types from which to choose: square (profile) guide rail and round guides (shafting). Your application will dictate which type of linear guide should be used.

Square guide rail is well suited to high-load applications that require good rigidity and high accuracy. These linear guides achieve their performance through the precise grinding of the ball tracks in the rail, which have close conformity to the balls. The classic application for profile rail bearings is in the machine tool industry, where load capacity, rigidity and accuracy are paramount. Round guides offer several advantages of their own, including the ability to run smoothly when mounted to less-than-perfect surfaces or used for vertical movements with heavy loads.

For a more detailed analysis of choosing square or round linear guides, click here.

Round Rail vs. Square Rail Technology

Mounting Options for Round Shafting

Choosing a Thomson Shaft Support

Round vs. Square – Linear Guide Rail Basics

Linear Bearings and Guides – Design Applications

Bearing Shafts Training

Design and Theory

Shafting is a key component in many linear motion machines and devices. Though shafting was designed for use with linear bearings, it is also useful for many other applications. 


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Product Details

Thomson shafting is available in several tolerance ranges or classes:

  • L - Larger
  • S - Smaller
  • N - Needle
  • D - Die Set
  • XL - eXtra precision class L
  • MM - Metric
  • AL - Aluminum
  • G - Groove (Class L shaft with a groove)
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