Someone sent me a sample of some crap they dug out of a bearing. The bearing is a self-aligning tapered roller bearing. The have not done a very good job installing it correctly even though these bearings are a bit more forgiving than most. They also didn't do a very good job at keeping up with their greasing frequencies.
All that said, took some of the junk, rinsed with heptane, filtered out the fines and put a magnet to the stuff left over. This is what I pulled out - a perfect example of what is known at cutting wear which is caused by the cutting in of debris (typically wear debris) and gouges out this strip of metal. Occurs mostly in under-lubricated bearings with previous wear debris from spall particles or in limited scenarios fatigue propagation.
This is the type of thing that I am going to use in my next book "The Wear Debris Encyclopedia". For real!
