I've used my fair share of attachments over the years and while not a journeyman by trade I've done my fair share of repairs/repairs at home. In all my years I've seen dull bread knives with more cutting potential than these bits. At slow speed, in softwood (hemlock), I shouldn't see the drill bit bend before it goes through the product. Probably a good deal for the money, but for the frustration and time spent waiting for the hole, I had time to watch three gallons of paint dry.