I recently received KG’s CBN 160 and 1000 grit wheels and have only 3.5 weeks of time sharpening on them. I fully and thoroughly understand the care they require to prevent loss of embedded grit. The exception is the definition of excessive pressure. I use significantly less pressure on CBN wheels as I did on the SG-250 however last night after sharpening a couple of knives, I removed the water trough, emptied the water into a sink and was surprised to see a significant amount of black particles with a density sufficient to rapidly and completely settle, leaving the water very clear. I don’t remember seeing this before. I’m already paranoid about using excessive pressure and, frankly, using one’s nail beds to gauge proper pressure is a very poor measure, at least for amateurs like me. Depending on the picture of a fingernail you review, the nail bed is located anywhere from the middle of the nail back to the nail/finger interface. And depending on the angle of the fingers when applying pressure on the jig, the pressure to produce a color change varies widely. My questions are: (1) am I simply obsessing over an insignificant issue, (2) Are the presence of these particles commonly seen using CBN wheels and most likely metal removed from the knife blade, and (3) can anyone provide a better measure for gauging pressure?