I was in Harbor freight and tool earlier this week and saw a 3 piece set of diamond sharpening stones.( coarse, med and fine grit)The price was about 12 bucks for them. Has anyone tried their sharpeners? I know they are pretty cheep, but I hate to buy something that is below par. Any input would be appreciated. I know they are pretty cheep, but I have in the past found a few tools that worked well that were reasonabley priced