This is a bit difficult to describe accurately with words. I wonder if anyone else has experienced this but at least a couple of my ball bearing folders would develop sporadic gritty clicks. They were smooth in the beginning and are still smooth but over time this one or two gritty clicking noise would show up though it is not that they are present every time the knives are opened (hence sporadic). It almost sounds something is inside the pivot area but I see nothing after disassembly; flushing with water won't help either. Is it possible that some balls in the bearings are no longer perfectly round? Or could it be because of the groove/trace developed on the titanium side of the pivot area? Or maybe the issue is in the detent ball / blade interface?