What I meant by not "getting" it had more to do with questions (2nd sentence in my paragraph) concerning the two different lockbar types and relative wear patterns. I hadn't really thought it through, so this morning did a bit of reading as well as getting out my 3 21s to compare wear patterns to those on my 25, 'Zaan, and Inkosi.
Reading helped remind me that the strength and stability of a frame (or liner) lock is dependent on the spacing within the triangle formed by the pivot, stop pin, and lockramp/lockface interface. If the knife is properly designed, as of course CRKs are, that spacing along with other factors makes for a locked blade that will not roll (rock). If that spacing changes significantly over time due to wear, then the tendency toward blade roll can increase.
Looking at the wear patterns on my 21s, then on my ceramic ball knives after wiping them clean, I can see the wear on the LRs has progressed along its breadth changing the spacing within the locking triangle. On the ceramic ball knives, that wear has progressed at a right angle to the aforementioned and has not discernibly moved in the other, keeping the distance amongst the points of the locking triangle observably unchanged. Also, while some material must have been removed from the LR by the ceramic balls of my three knives, I certainly can't feel any groove running an object similar to a toothpick over it.
In short, the ceramic ball makes the point of LB/LR contact predictable given its specific location both initially and as the knife's action wears in. I never did think that CRK, whose design engineering is excellent, would adopt such a significant change without careful consideration or would continue to use that design and include it in new models if it didn't prove out. Personally, I don't tend to think of things in terms of warranty, but your point concerning that is well taken. As always, thoughtful commentary by BF members can lead one toward better understanding.
