There is a sort of point to relief grinding, Joe. By having only the leading edge of the reel blades close to the bedknife, the remainder of each blade has so much clearance that there is no real possibility of smearing the end of the grass leaves, as more or less inevitably happens with a conventional grind when the leading edge is even microscopically rounded. To see what I mean, just try using a lathe cutting tool with no clearance angle. Cutting pressures become enormous, horsepower required goes way up, the tool overheats, the chip looks woeful, and the surface finish on the machined surface is awful. There are two important problems with relief grinding, however. First, the tiniest amount of leading-edge wear (grass is rather abrasive, so there always is leading-edge wear) increases the blade to bedknife clearance and changes the whole cutting setup. Second, the reel blades are consumed more quickly with relief grinding, due to requiring more frequent sharpening. (There is a third "disadvantage" that I don't personally care about: you can't backlap a relief-ground reel, since that would immediately remove the relief-ground clearance on the blades. I don't care about that because I disapprove of backlapping, which is likely to lead to a wavy blade and bedknife.)
