AS9120B, ISO 9001:2015, and FAA AC 0056B Accredited

How to Properly Mount Bearings?

Bearings are components found in countless moving assemblies, facilitating and constraining motion while mitigating friction between moving surfaces. Bearings also come in numerous types, including variations such as the cylindrical bearing, rolling bearing, plain bearing, and more. When one procures and implements bearings within an assembly, it is important that they are handled and mounted correctly for the means of protecting the bearing and ensuring that it will perform optimally. If bearings are not cared for prior to and during the mounting process, they can face excess wear and tear, presenting the possibility of part failure which can lead to assembly damage—or worse. In this blog, we will briefly discuss bearing mounting, ensuring that your bearings are implemented correctly for their optimal functionality.

When bearings are initially procured, it is important that they are well protected until they are ready to be mounted. Until it is time to apply the bearings in an assembly, they should be kept within their original packaging so that there is the lowest chance of them becoming contaminated or rusted. When bearings are intended to be used for standard operations and/or are pre-lubricated, it is important that oils are not cleaned off as they serve to enhance operations and protect the component itself. If the bearing is to be implemented in an assembly exhibiting high rotational speeds, however, then the anti-corrosion oil should be safely removed before installation. With any application, the bearing should not be removed from packaging or cleaned until the moment before installation.

Once the bearing is prepared, the shaft and housing should both be cleaned and inspected to check for any potential flaws or damage that occurred as a result of machining. When removing any lapping agents, chips, or casting sands, care should be taken as to protect the bearing. Once that is done, the housing can be cross compared to included manufacturer drawings to verify dimensions, finish conditions, and forms. If everything matches, machine oil can be applied to the fitting surface prior to mounting.

In regard to the bearing mounting process itself, such procedures will differ based on the type of bearing that is being used. If the bearing is a general type, then an interference fit will need to be implemented on the inner rings while a clearance fit will be applied to the outer rings. If the outer ring of the bearing rotates, then an interference fit will be used instead. During the installation of fittings and the removal of rings, it is important that proper force is utilized. Generally, bearings will differ on the force that is required for fitting installation and ring removal, that of which is determined by the finish of shafts, the amount of interference that is permitted by the bearing, and other factors.

For a cylindrical bearing bore, as an example, mounting can be conducted through a few methods. The first is to use a press fit, that of which is the most common method that is carried out with the use of a hydraulic pump. For a more simplistic installation, bolts and nuts may be used, and the screw hole should be at the shaft end. If neither method can be utilized for any reason, then hammers can be relied on. With hammers, however, it is crucial that force is applied carefully as some rolling bearing components can easily become damaged. However, even with the use of a press fit, there are certain things that one will have to be careful of.

While it is important to know the proper methods for mounting bearings, it is also crucial that bearings are removed properly when a replacement is needed. Oftentimes, outer ring bearing puller tools, presses, and other specially designed equipment pieces are best for their safety, efficiency, and damage prevention capabilities. Separator or knife type tools, as well as heavy-duty pullers augmented by hydraulics, are also useful; though, such equipment poses the risk of causing damage. As a result, care should always be taken when carrying out such processes. Additionally, a bearing that is removed from an assembly should not be used again, even if one was careful during the uninstallation process. As such, the importance of avoiding damage during removal is so that the bearing can be inspected for any signs of damage that may have occurred from standard operations.

Aviation Sphere is an online distributor of aircraft parts, and we are your sourcing solution with over 2 billion new, used, obsolete, and hard-to-find items in stock. With an expansive inventory that caters to a diverse set of industries and applications, we can fulfill all your operational needs with top-quality items offered with competitive pricing. Get started with a personalized quote on the products that you are most interested in when you fill out and submit an RFQ form through our website. Once received, a dedicated account manager will reach out to you in just 15 minutes or less to continue the purchasing process. Experience the future of part procurement today when you get in contact with a representative at Aviation Sphere.


Recent Twitter Posts

Semiconductor's Certifications and Memberships
The only independent
distributor with a
  • All Orders are Fulfilled in the U.S.A
  • All shipments must comply with U.S.A export laws.
  • No exceptions.

“We Proudly Support Intrepid Fallen Heroes Fund that serves United States Military Personal experiencing the Invisible Wounds of War : Traumatic Brain Injury (TBI) and Post Traumatic Stress (PTS). Please visit website ( and help in their valiant effort”.

Thank You for Visiting.

We Hope that You Will Visit Us Again the Next Time You Need NSN Parts and Make Us Your Strategic Purchasing Partner.

Request for Quote

We use cookies to ensure that we give you an amazing experience on our website. If you continue to use this site we will assume that you are happy with it.