Thin Section Bearings

The UNASIS range of split thin section bearings are used by design engineers to optimise the use of limited space whilst keeping the flexibility needed to create innovative and cost-effective solutions.

Share This Page

These lightweight bearings allow for the production of lightweight precision assemblies by combining the best qualities of standard solid ring thin bearings with an added freedom in design. Their standard 420 stainless steel with NYLON cage is designed to be the best option for a range of crucial industries such as space, defence, nuclear research, ultra-high vacuum, and semiconductor.

These specialised bearings are both lightweight and compact, ranging from 4.5mm to 12.7mm. Their innovative cage design and split assembly methods allows for maximised load capacity and a very high ball complement. Supplying these specialised bearings with rollers in cross and angular configurations can further increase capacity.

The innovative design of the split inner and outer ring allows the bearings elasticity in mounting over features in the mating components. Once mounted, the shaft and housing are relied on to control the clearance or preload, giving more control to the manufacturing and assembly of the product.


More About...

Infinite Preload Control

Lightweight Slewing Rings

Bearing Mounting Advantages

Custom Thin Section Bearings

Industry-Beating Lead Times

Cost Savings

Selection Design Advantages

Installation of Split Thin Section Bearings

Due to the split inner and outer ring design, bearing preload in split thin section bearings is determined by the shaft and housing fit. As a result, the internal clearance or preload settings can be set at the design stage of the application, lowering the potential costs of requesting special preloads to be set during the assembly stage of the bearing.


Our innovative manufacturing process allows for large bearings to be produced with extremely low radial runout, making them excellent for applications requiring precise accuracy.

Our split thin-section bearings are available to be supplied either as a stand-alone product or fully integrated into our range of slewing ring bearings. Due to their lightweight, heavy duty, and high-precision characteristics, they are suitable for a variety of applications including tank turrets, naval gun mounts, and satellite gimbals, radar systems, and ancillary products. We have a wealth of manufacturing experience enabling us to accurately and reliably create lightweight slewing rings with split thin section bearings for applications where large masses require swift, ultra-precise movement from bearings packaged into the tightest spaces.

The enhanced elasticity of a split thin-section bearing can provide an advantage to your production assembly procedures. Specialised features can be flexibly machined into the shaft and housing components all while maintaining a low cost as the bearings can be manoeuvred over and around these additions.

Thanks to the innovative manufacturing method used to create split thin section bearings, custom sizes can easily be accommodated with a one-off tooling cost that allows the bearings to be manufactured to exact dimensional requirements and diameters up to 5 metres. This allows for the bearing to be manufactured around the application instead of the other way around.


Our engineers are on hand to provide expert guidance on load and speed information for specific requirements and use our bespoke bearing calculation software to calculate the speed and life cycle of a bearing. We can also predict a product’s reaction to real-world forces such as heat, vibration, and fluid flow using our in-house programmes such as Solidworks and Finite Element Analysis (FEA) to guarantee all customers a premium service.

Compared to that of a standard thin-section bearing, the lead time of a split thin-section bearing is considerably lower due to our innovative manufacturing process. To do this, we use a flat bar which is precision machined in a linear profile before being shaped.


As standard, these high-performance races are made of corrosion-resistant 420 stainless steel. However, the stainless-steel balls can be swapped for silicon nitride ceramic, industrial ruby, and M50 tool steel upon request. The standard NYLON cage can also be substituted with PEEK and stainless steel as required.

Before being formed into their traditional round bearing shape, the range of UNASIS split thin section bearings are manufactured using state-of-the-art linear precision grading and machining. This innovative method of production is advantageous by significantly reducing lead times and the overall expense of the manufacturing process, especially with high-volume production. This also leads to the high-precision class.

What truly elevates the UNASIS split thin-section bearings from traditional bearings is the raceway split. The likelihood of atmospheric conditions impacting the bearing is significantly reduced as the rolling elements do not move in a solid raceway. In addition, the race elasticity allows the easy accommodation of variables within the application designs such as shocks, vibrations, temperature fluctuations, and other external forces.

Pressure should only be applied on the outer ring when thin-section bearings are being installed into housing. When being installed on a shaft, they should be pushed on the inner ring. A clean and contamination-free installation area is recommended since the majority of these products are open and unsealed.


For more in-depth instructions about the installation of our split thin section products, please refer to our technical article.

Split Thin Section Ball Bearing

Split Thin Section Roller Bearing


Fast Delivery

As our split thin section bearing range is manufactured from wire stock rather than bar, they are always readily available. Compared to traditional non-stock thin section bearings that typically take 24-40 weeks to be delivered, our range can be as quick as from stock to a maximum of 4-5 weeks, helping to keep your machines in service.

Split Races

The unique split design enables design engineers to explore new design aspects with ‘never before possible’ application geometry, as well as many other advantages over standard thin section bearing alternatives.

High Ball Compliment

The UNASIS bespoke thin section bearing offers a range of unique benefits thanks to its innovative split race design that offers a substantial increase in ball complement, for example:

  • Higher rigidity
  • Greater dynamic and static load rating
  • Greatly increased durability
  • Reduced radial runout

420C Stainless Standard

As standard, all of our bespoke split thin-section bearings are made using 420 stainless steel rings. This provides high corrosion resistance and significantly reduces maintenance requirements.

Low Mass

The mass of an application can be greatly reduced in comparison to a standard thin section bearing because of the thin structure and increased load capabilities.

Highly Customisable

The innovative yet simplistic design of the UNASIS split thin section bearings create a highly customisable bearing, enabling you to choose from:

  • Alternative ball types such Ceramic balls
  • Different cage material options such as PEEK or Stainless Steel
  • Custom bore dimensions
  • Designing-in as an integral part of a rotating mass in parent materials of aluminium, steels, copper etc.

Constant Cross Section

Solutions can be designed with an ultra-low profile as UNASIS split thin-section bearings offer a constant cross section, allowing them to still produce extreme smoothness and precision even with large shaft bores.

Fast Delivery
Split Races
High Ball Compliment
420C Stainless Standard
Low Mass
Highly Customisable
Constant Cross Section


UNASIS Bearings has a vast network of distributors to reach all corners of the globe. No matter where you are, you will get the best service to go along with the best bearings.

Contact Us Today

For more information, please call us today on +44 (0) 1235 527 770 or email [email protected]

First Name*


Last Name*


Email Address*








I would like to receive marketing from UNASIS via: