Prevention is better than a cure: Your checklist for correctly handling rolling bearings

Bearing maintenance is very important to prevent machines from breaking down prematurely. The correct mounting and adjustment are, of course, essential for long-lasting bearing performance. But maintenance is also vital: it reduces safety risks and unscheduled downtime and keeps your repair costs low. In cooperation with bearing manufacturer Schaeffler we have produced a number of articles to give you expert guidance on the correct handling of rolling bearings.

Welcome to Part 2: your handy checklist.

Optimise the service life and performance of rolling bearings and save time, labour and costs with this handy checklist,  composed  together with bearing expert Schaeffler. Please note that you can do most of the work yourself, but for certain procedures  it is  better to ask for help from a specialist.

 

1. Handling bearings
Rolling bearings are made of hardened ball bearing steel, which is generally not corrosion-resistant. So, you should always handle rolling bearings with clean, dry hands or use clean gloves. This prevents corrosion and contamination. It is very important to ensure that no contamination can penetrate the bearing, especially when handling bearings without a seal.

 

2. Storing bearings
If possible, keep bearings in their original packaging. Do not remove a bearing from its original packaging until you need it for mounting. If you no longer have the packaging, pack the bearings in VCI paper (vapour corrosion inhibitor paper) and/or a plastic bag. They should be stored in a cool and clean environment with low humidity and free from dust, vibration and shocks. An extra tip: Never store bearings upright, but always lying down. And, of course, make sure that you have a clean workplace if you have to put a bearing down somewhere before mounting or after disassembly.

 

3. Cleaning bearings
New bearings are provided with a  preservative oil that in general  does not have to be removed before mounting. If a bearing is reused, it is advisable to clean the bearing thoroughly with a solvent and then immediately re-coat the bearing, for example with an anti-corrosion oil. Use lint-free cloths to clean  the bearing and any adjacent structural parts. An extra tip: designate certain containers exclusively for cleaning bearings and do not use them for any other purpose.

 

4. Installing bearings
If a rolling bearing fails prematurely, around 16% of the time it is the direct result of poor mounting. The fundamental requirement is that mounting forces must never be transmitted through the rolling elements when mounting. Also,  never  hit the bearing rings directly with anything, such as a hammer. Before mounting, make sure that all components are of the correct dimensions and that they are clean and undamaged. Some bearing types, such as angular contact bearings or tapered roller bearings, often have to be adjusted with a certain amount of play during mounting. Make sure that you know the pertinent clearance data at the time of mounting. The precision required means it is usually wise to seek the assistance of a specialist during installation. If bearings must be lubricated during mounting, check whether the correct lubricant is available (paying attention also to the expiry date!) and what the prescribed amount of lubricant is per bearing.

 

5. Using suitable tools
Special tools are available for the mounting and removing of bearings, e.g. bearing pullers, mounting kits, induction heaters and hydraulic nuts. These tools are especially designed for a smooth mounting or removal process, so that the risk of damage is kept to a minimum.

 

6. Inspecting the bearings
In order to detect deviations or damage before they cause problems, it makes sense to check bearings regularly. Changes in temperature, sound or vibration can indicate a bearing problem. The quality of the grease that comes out of the bearing during re-lubrication can often be used to determine the condition of the bearing itself. After disassembly, you should inspect each bearing carefully before deciding whether it can be reused or should be replaced.

Looking for correct lubricant for a rolling bearing? Read about it here. For more information, please visit www.kramp.com. Or contact your account manager.