I've been drilling through telephone poles all day and for too long I've been using the 1/16 size too large which creates a wobble which is really annoying. This affects me and only matters because I've put that WoodOwl through hell and abuse and she keeps coming back for more. No signs of blunting, glides on like day one. This type of stuff has many half-price competitors that look so similar it's amazing how they tend to bind sawdust and just suck. If you're here to decide "um, $40 or $20," then you need this $40 guy. (rough price estimate) Thanks WoodOwl.