Installing Split Thin Section Bearings

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The bespoke nature of the UNASIS split thin section bearing enables it to support previously impossible assembly geometries. Thanks to their innovative design, the inner or outer ring can be placed in either the housing or shaft groove. To ensure assembly is not possible if both rings are in the groove, at least 1 retainer should be used in this process.


The un-retained bearing ring must be fitted first during this recessed bearing assembly method. We will assume that this is the inner ring in the following examples. The two possible fitting methods are as follows:


  1. The bearing is passed axially along the shaft until it is correctly loaded, see the drawing below. This is the preferred installation method.
  2. The alternative method concerns rotating the bearing onto the shaft held in a helical form. The ring is then manoeuvred into position using a similar method to threading a nut to a bolt. This is only suitable if the bearing groove is close to the shaft end. Please contact us for this distance in each application.


The bearing’s split should never be passed over the shaft radially, as the excessive stress on the bearing ring can cause irreversible damage.


The next step is to fit the cage, balls, and outer ring before locating them within the housing. After that, the outer ring is retained. If you are unsure of a suitable retention method, please contact us.


We can provide the required fitting tolerances for both the shaft and housing. Typically, these fits would be h7 and H7 respectively.



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.

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

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