I used to sharpen blades a lot when I shot Thunderheads.......I have this little wheel clamp deal that you lock the blade into and the work over different grit automotive sandpaper. The final strokes were simply 2 passes over the finest grit, and then youVERY carefully set them aside.
I could get those blades so sharp they were absolutely FRIGHTENING. Quite honestly they were the sharpest objects I have ever seen to this day.

They didn't shave hair.......the hair actually jumped off your skin with even the lightest effort.[:-]I have never seen a factory blade that came close to these sharpened ones, not even the best Rocky Mt. or NAP blades.
I still have that wheel downstairs and trust me, if you Thunderhead shooters saw what it can do to even a factory fresh blade you'd give me $100 for the thing.