Well, you must be recieving a lot more consistant DMT 325's than I have. The last 4 I have bought came new with some loose, high diamonds and were not suitable for anything until "smoothed out" somewhat. I have spoken to several others who agree. By rubbing with the shaft of an old screwdriver, as I said, these high diamonds are knocked off and the plate is evened out. I like a smooth finish on my stones. Newer DMT's leave gouges and scratches, so I won't even use one for flattening until it is practically useless for chips, bevels, knives, etc. Rubbing on pavement? I don't think so! Each to his own, though!