Bearings are an essential component for many pieces of machinery and equipment. When it comes to the service life of bearings, the brand and model quality are important, but proper bearing installation is even more crucial. This guide will lay out what is involved in a quality bearing installation from expert bearing installers and which techniques and shortcuts should be avoided in order to get the most out of your bearings.

Why Proper Bearing Installation Is Important

Did you know that 48 percent of bearings fail before the end of their expected service life due to improper installation or mishandling? Avoid improper bearing installation practices that use imprecise shortcuts, such as a hammer or a torch. These practices can result in premature failure or safety hazards. Proper bearing installation is vital in order to achieve a full component service life, reducing downtime, and increasing workplace safety.

What to Expect From a Quality Industrial Bearing Installation

While some can talk a big game in regard to their maintenance skills, it’s important to recognize what differentiates a good installation from a poor one. This guide will lay out the proper bearing installation steps for non-housed bearings.

Step 1: Practicing Good Installation Preparation Habits

With busy schedules and many maintenance projects to get to, it’s important to take a moment and ensure that you are practicing good installation preparation habits. Before the installation, maintenance personnel should familiarize themselves with the proper safety and job procedures. This will ensure they understand the process. Bearing installers should follow these preparation steps:

• Brush Up on Safety Protocols and Bearing Installation Procedures: Consult your company’s or the manufacturer’s equipment maintenance procedures and brush up on the required maintenance steps for your bearing installation.

• Use Proper Tools and Safety Equipment: Investing in the correct bearing installation tools will result in cost savings by reducing labor hours as well as increasing machine uptime and service life. The cost of the proper installation tools will pale in comparison to the potential damage, hazards, and downtime of a poorly installed bearing. Safety equipment is also key in any industrial setting.

• Keep Bearings Clean and Dry: Always leave bearings in their packaging and store them in a safe, dry place until they are ready to be mounted. Once opened, handle the bearings with clean, dry hands or with gloves. The fewer contaminants that get inside the bearings, the longer the bearings will last.

• Keep Work Surfaces Clean: Use a fresh piece of paper or plastic to work on, and never set components anywhere outside it. All mounting and housing components should be clean. Use an industrial Scotch Brite pad to remove any dirt or a fine file to get rid of any rust or burrs. Keep rust or burr residue away from other clean components.

• Check the Dimensions Carefully: Measure the shaft and housing diameters to ensure the chosen bearing is the correct size and that the shaft and housing are truly round. Do not use the bearing as a gauge for this.

Step 2: Removing and Examining the Old Bearing

The first step to replace an industrial bearing is to remove the old one. Bearing pullers and presses designed for removing bearings are recommended because they increase safety, reduce labor, and minimize damage to the shaft and housing. Two- and three-jaw mechanical pullers evenly pull on the outer bearing ring to reduce damage to the housing and shaft. For heavy-duty bearings, there are hydraulic bearing removal tools that make removing difficult bearings easier. We recommend using bearing pullers and presses for bearing removal. The key is even and equal force to remove the bearing. There are other removal methods, but many are either dangerous to the technician or can damage the shaft or housing. The old bearing should be examined to determine the cause of bearing failure, and the root cause of that failure should be addressed.

Step 3: Determining the Best Industrial Bearing Installation Method

The three best methods for industrial bearing installation are mechanical mounting, hot mounting, and hydraulic mounting. Your maintenance technician will need to determine the best method for installing the new bearing. The manufacturer will often recommend an installation method that works best for that bearing, and that method is typically influenced by the size or type of bearing.

• Mechanical or Cold Bearing Mounting: This method is often used for smaller bearings with an internal diameter of up to four inches. Mechanical mounting is more convenient than other methods. Once properly seated, the bearing is driven onto the shaft with a special fitting or drive tool to exert equal force on it at the same time.

• Hot Bearing Mounting: Hot mounting is used for bearings exceeding four inches in diameter. The bearing is heated up, and the heated material expands, allowing the technician to install it on the shaft. When the bearing cools down, the material shrinks and locks the bearing into place on the shaft. There are different ways to heat a bearing, but many introduce contaminants. The best way to heat a bearing is with an electric induction heater.

• Hydraulic Bearing Mounting: For extra large bearings, the hydraulic mounting method uses a hydraulic press to mount the bearing. The shaft needs oil ducts or grooves so that enough lubrication can be used to reduce friction while the bearing is physically positioned.

Step 4: Installing the Industrial Bearing

The maintenance technician will then proceed with installing the bearing with the following steps:

1. Cleaning the Shaft & Housing

Before opening the new bearing packaging, it’s important to ensure the shaft is clean and does not have any burrs. Many industries use emery cloths to remove rust and clean shafts, but it’s important to remember that emery cloths are essentially sandpaper, and tiny particles are left behind when using an emery cloth, which can contaminate the bearing. We recommend using an industrial Scotch-Brite pad to clean the shaft and housing, followed by a light machine oil to remove moisture.

2. Double-Checking Measurements & Tolerances

Next, measure the housing bore and shaft with a slide caliper or micrometer to ensure they are within the recommended tolerances for the bearing and machine. Take several measurements along the length of the shaft.

3. Installing the Bearing

Finally, it’s time to install the bearing. It’s vital that the bearing is handled with care and installed with precision. Bearings, despite being made of steel, are surprisingly delicate. Maintenance technicians should take great care in not dropping the bearing and keeping it clean. They should avoid unwrapping the bearing until it is ready for installation. Bearings nowadays come with factory lubrication, and lubrication should not be wiped or cleaned unless the installation instructs you to do so. The technician should use one of the bearing mounting methods listed above to install the bearing. They will check for proper bearing fit and ensure everything is properly aligned.

Step 5: Using the Correct Bearing Lubricant

The bearing may or may not call for additional lubrication after installation. It is crucial to use the correct bearing lubrication as indicated by the manufacturer. Lubrication reduces friction and significantly increases the service life of any bearing. Some studies show as much as 80 percent of bearing failures are due to improper or incorrect lubrication.

What to Avoid in a Bearing Installation

As our knowledge of industrial machinery has increased, we have learned that techniques of previous decades are now outdated. Here are some techniques regarding bearings that may be used in rare circumstances but are generally not recommended due to safety concerns or potential damage to shafts and housing.

Bearing Removal Techniques to Avoid:

• Using Brute Force to Remove the Bearing: Don’t use a hammer or tool to try to beat or pry the bearing from the shaft manually. This requires a high level of force, and it is difficult or impossible to exert force equally on the entire bearing. Brute force often results in damage to the shaft or the housing.
• Cutting the Bearing: Another method to avoid is to cut the bearing off of the shaft. Again, this can often result in cuts and nicks in the shaft, which are not repairable. Cutting is a last-ditch effort that should be avoided if possible.
• Using Hot Oil or Steam to Expand the Bearing: Don’t heat oil or steam to a high temperature and use that temperature to expand the material of the bearing so it can be slid off. We do not recommend this method because it is extremely dangerous to the technician and can result in severe burns. It can also damage the surrounding machinery, which may lead to further repairs and costs.

Bearing Installation Techniques to Avoid

Hammer Installation

Hammers should not be used to pound on one side of a bearing. Exerting force on one side of the bearing will stress the bearing and can cut into the shaft. Instead, use a bearing driver and a dead blow hammer. There are a variety of bearing drivers depending on what bearing you are installing. A great option is a bearing driver that consists of a metallic tube and polymer impact rings to spread out the force and dampen the impact. This kind of driver can be used with bushings and oil or grease seals without damaging them.

Oil, Steam, or Torch Heating

To install a press fit bearing, it needs to be heated. There are many ways to heat different materials, but we do not recommend any heating method that may leave residue in or contaminate the bearings. Oil, steam, or even torches all leave contamination in the bearings and will shorten their lifespan. Avoid oil baths and propane torches. A pizza oven can work in a pinch, but we recommend a modern bearing induction heater.

Cooling Shafts

Usually, bearing installation methods involve heating the bearing itself to get a perfect fit. One technique that some technicians have used in the past is to place the shaft outside in winter and leave it out overnight so that the cold would shrink it. While this method does work, it brings the shaft into contact with moisture, which creates corrosion problems. Another solution is to cool the shaft with liquid nitrogen. Liquid nitrogen is better than leaving shafts out overnight, but this technique should only be used in extreme interference fit cases. Water is a byproduct of this process due to the rapid temperature changes and relative dew point, which creates rust. The best option is to use a bearing induction heater on the bearing, which eliminates the risk of moisture. Do you need help with your equipment maintenance? IBT Industrial Solutions offers expert bearing and machinery maintenance services. We also offer in-person training to train maintenance staff on the proper processes, procedures, and tools to maintain equipment. Contact us to learn more about our services and how we can help you and your equipment.