Review on IRWIN Tools Countersink Set 5 Piece - Model 1877791 by Kevin Apriando

The first one I used in aluminum was a little off center but it wasn't terrible so I figured this set would make a decent cheap backup set. Today I used two others and they were absolutely awful. Extremely non-concentric and vibrates horribly when used in a drill press. For those who don't know, concentricity is basically evenness with respect to the central axis. In other words, as the tool rotates, the tool and all cutting surfaces maintain consistent contact with the workpiece, minimizing vibration. If it's that bad with aluminum, then I don't even try it with steel. They'll probably work in wood, but if that's all you need, buy one of the really cheap sets because they're no worse. I don't think Irwin is a great brand but I expected more. Maybe I was just unlucky and got a bad set, but I won't try any other set.