best grinding tool for sharpening | LawnSite. Jul 24, 2017· have done the bench grinder ( to hard to get the angle needed ) have done the 4" grinder with high grit number wheel ( 60100 ) and had good results ( have to make quick swipes to keep from burning ), also used a 9" hand grinder, quick one swipe and takes off lots of material quickly if the blade has big damage ( stone nicks or a ...