It does look like a worthwhile tool Deejay - I've watched a guy do the operation on-the-job in my backyard on a big ATCO mower, using a hand-held oilstone, and I wasn't convinced he was getting the front face square to the top face of the blade, though he was certainly trying. What I don't understand, though, is how that little gadget keeps the front face from being sharpened more in the middle than at the sides, so it finishes up hollow in the center. As you know, the cutting edge has to be perfectly straight and exactly parallel to the axle of the cylinder if the mower is going to work.
