I used these stones recently while helping my brother change a differential on his Jeep TJ. I didn't know which sharpening stones would work best, so I tried these. They act just like a quality bench grinder, perfectly balanced on my 25,000rpm Dewalt die grinder and cut through bearing races with ease! Without this quality stone, it would not have been possible to remove the original rear axle needle bearing. Got 3 but one got the job done with little wear! A HIGHLY RECOMMENDED sharpening stone for all heavy-duty sharpening jobs!