Pillow block ball bearings are used in numerous machines across different industries. They get the job done and are reliable (when installed the right way). But small mistakes during installation can cause big problems later.
Even a high-quality bearing will fail early if it’s not handled correctly. Below are five common mistakes to avoid when installing Pillow block ball bearings .
Keep reading to make sure you don’t encounter these problems firsthand!
1. Using the Wrong Shaft Fit
The bearing must fit the shaft properly. If the shaft is too small or worn the bearing won’t lock in place. It may slip during operation. This leads to wear and heat buildup. In time the bearing will fail.
Always measure the shaft before you install the bearing. Use a caliper or micrometer. Make sure the surface is clean. No rust. No damage. The bearing should slide on smoothly. It should fit snug. Never force it. Never install on a damaged shaft.

2. Overtightening the Locking Device
Pillow block ball bearings have locking systems. These include setscrews, clamp collars or eccentric locks. Their job is to hold the bearing in place on the shaft.
Many people overtighten these locks. That causes damage. A crushed inner ring can lead to misalignment. It also puts stress on the bearing and shaft.
Use the correct torque. Use a torque wrench if needed.
Tight is good. Too tight is not.
3. Misalignment
The bearing must line up with the shaft and the rest of the system. Misalignment puts uneven force on the bearing. This causes early wear and failure.
Check that the bearing is straight. Use a level or straightedge. Make sure the shaft runs true. The housing should sit flat. Take time to check your work before you tighten everything down.
4. Uneven or Loose Mounting Bolts
The housing must be firmly attached to the mounting surface. If the bolts are loose or uneven the bearing can shift during use. That causes vibration and misalignment.
Start bolts by hand. Then tighten them in a crisscross pattern. Keep the pressure even. Use the right bolt size and strength. Avoid soft or short bolts.
If the surface is uneven be sure to use shims or machine it flat. A solid base keeps the bearing stable.
5. Skipping Lubrication
Bearings need grease to work well. Without it they heat up and wear out. Some people forget to grease the bearing after installation. Others use the wrong type of grease.
Check the specs. Use the correct grease for the bearing and the job. Don’t mix greases unless they are compatible. If the bearing is sealed and pre-greased don’t add too much. Too much grease causes heat and pressure.
Set a schedule to re-grease the bearing. And keep in mind: fresh grease helps bearings last longer and run cooler.
Pillow block ball bearings are built to last but only if installed the right way. Bad shaft fits and poor lubrication are the most common causes of failure.
Avoid these problems by following basic steps. Measure the shaft. Line up the bearing. Tighten bolts evenly. Use the right grease. And above all else always slow down and do it right the first time.
Our team here at NSAR Bearings provides reliable Pillow block ball bearings for all types of machines. We also offer OEM options and technical support. To learn more be sure to check out nsarbearings.com and browse everything in our shop!