Grinding wheels wear from left to right. You dress it to a certain diameter and then particles come off the left part before they come off the right. That way S

Grinding wheels wear from left to right. You dress it to a certain diameter and then particles come off the left part before they come off the right. That way SOME fraction of the width is at the proper diameter. This is why you never ever grind full width. Of course, once you grind long enough that you wear the whole width, game over.