ball bearings without grease

Well it depends on how far the failure has progressed, but you will start with spalling in the load zone on the outer race, so in your case, the bottom 1/3 of the outer race will show a track of spalling that starts at a point, progresses at the bottom to be the width of a ball, and the tapers back to a point.

As the failure progress, the balls will begin to spall as well, and eventually the inner race will be spalled 360 degrees.

Now I have made a lot of assumptions here, so more details on the bearing would be helpful. Type and size? Is it radial only, or radial and thrust? Back to back arrangement?

exactly so you are dead on,the bearing has huge play at one spot only.

Contact:

John.P.Baker@skf.com

He should be able to help you.

Hi,

this may be much more complicated.

There is very likely a wear pattern at existing lubrication:

A.: spalling at overload (weight, vibration, unbalance, bad mounting procedure, bad fits at shaft or housing, tilted axial fits, bad bearings, dirt and wear particles)

B.: fine particles genrated by wear in fine tracks around balls and raceways, these thickening the lubricant until dry,

C.: (frequent in generators and motors) periodic small surface deterioration very shallow but very noisy xausing overload and gross failure (spalling) - caused by stray voltage and current that starts electro-erosion.

If all these are controlled to be at an acceptable level then a small amount of lubricant will last for years to decades.

Teledyne Systems Co. designed in the 70ies a permanent lubrication system for their superb inertial grade SDG5 gyro. One of its use was (and still is) in the orientation of the pioneer probes antenna to earth to bridge now 350 (or some more) million kilometers from the outer boarder of our solar system to us with only 80W of transmitter power.

This can be adapted to more ordinary machines if maintenance is costly.

RHABE

what can cause the inner race of a ball bearing(6328) to crack