Sometimes I still use one of these self-feed drills when I have to drill a large hole in thick wood, a large drill hole and too deep for HM cutter. Nails kill the edge which is tool steel and the self feed screw is good for softwood but any hardwood I come across in older homes and the screw pulls the cutter back faster than the blades. cut, and the hole cutter jams and twists the drill. Recommend using the least powerful drill you can get by with so you are less likely to injure yourself if you get stuck. MDF and OSB dull blades quickly, but you can use a thin Arkansas sharpener to sharpen, store, and sharpen them. In terms of speed, they are between the bi-metal hole saw and the HM hole cutter.