Rotate - Second Step in Checking a Radial Ball Bearing Cleanliness and Condition

2) Holding the bearing vertically, slowly rotate the bearing while grasping it between a fingertip and thumb.  When doing this, do not put any axial load on the bearing, but instead put a slight amount of vertical (radial) load on the bearing with your finger/thumb as you turn it.  It should feel smooth as you rotate it and should not feel gritty, rough or ‘choppy’ under the slight vertical load you are placing on the outer race.  Oftentimes you may feel a rough spot when you do this check, and this usually indicates a problem with the bearing: it may indicate that the bearing is still fouled with hard debris (sand, metal, etc.); a ball is damaged; the retainer (cage) is bent, or a race is flaked (e.g. dented).  [You can often rock the bearing back and forth across this point and ‘zero in’ on the rough spot.] If the bearing feels ‘generally rough’ while doing this check, this can indicate that a race may be worn or warped, or the retainer may be distorted.

If either of the first two checks fails, then re-clean the bearing and repeat both checks again.  If the bearing fails either of the first two checks again, then consider replacing it.  Bear in mind that these two checks only give a general status on the condition of the bearing.  It is still possible that both checks will be satisfactory, yet the bearing will be noisy and not rotate correctly when lubed and put back into the reel.  The reason for this is that the alignment of the components and loads that are carried can have a more significant affect on how a marginally worn or damaged bearing actually rotates, and the speed the bearing rotates at in the reel will usually be a lot higher.  However, the two checks can still be used to identify the majority of problems.  (If both tests pass satisfactorily, then you can lube the bearing and slowly spin it with a finger tip to disperse the lube.)

Damaged Races - (Left) Center Race Due to Misalignment, (Middle) Outer Race. Due to Corrosion, and (Right) Center Race Due to Mishandling (e.g. dropping?).

Here’s a tip that can save some heartache while you disassemble and clean your reels.  Cover your work space with a clean lint free terry cloth rag.  The terry cloth strands will help prevent parts from bouncing on your work bench and rolling away.  If you’ve ever had a precision bearing roll and fall from your workbench onto a hard floor you’ll appreciate this tip; because chances are that the bearing was damaged in the process.  A fall of this type can dimple a race, deform a retainer so that will no longer track correctly, and can even knock-out a shield on the side of the bearing.  You may not be able to readily see the damage from outside the bearing, but trust me, it probably occurred and chances are you’ll be trashing the bearing later.

The table below lists the symptoms, causes and solutions to several ball bearing problems.  Although the list only focuses on common problems, it can be used to troubleshoot the majority of them.

Ball Bearing Problems, Causes and Solutions

The noise (both audible and vibration) that a bearing exhibits can provide a lot of information on the type of problem that it experiences.  However, bearing noise is also influenced by the manufacturer’s design and internal construction of the bearing, materials it is made from, raceway finish and internal clearances; and these last factors really don’t have anything to do with the ABEC rating of the bearing.  Noise can also result from a bearing that is not mounted correctly in its socket; the load does not fit correctly in the center race; or the bearing carries a radial imbalance from the load.  Wear, lubrication, fouling and misalignment can also produce bearing noise as shown in the previous table.

Here’s a tip that can preclude ball bearing damage while performing maintenance on your reel:  Applying excess force across the inner race and balls to the outer race can actually damage a ball bearing. Ball bearings are designed to support little axial load, and if you push or remove a ball bearing into a tight socket by the center race, you can damage the bearing and not realize that it even occurred. [This is more likely to occur on pinion bearings, since the socket that they mount in usually employs a precision fit to hold the bearing.  In addition, it is very easy to get a pinion bearing stuck in its socket when installing or removing it, because it gets tilted.]  Always try to remove or install a bearing into its socket by pressing on the outer race.