As other reviewers have pointed out, the two oblique blades protrude slightly beyond the two smaller vertical blades. Not sure why they designed it that way, but it results in only 2 out of 4 blades making contact with the surface. I've used this on a Bosch router in a router carriage and while the finished surface felt smooth, I attribute this mainly to the freshness of the blades. After 15 minutes of use, I had to clean the racquet of resin and sawdust with a brass brush. And after 30 minutes of use I had to stop completely to remove the bit and soak it for an hour (50/50 water and detergent. works wonders to remove tar from any blade) to do as best as possible any remaining debris removing began to stick the blades and affect the cutting quality of the drill (i.e. a lot of burning). I love the idea of the swappable blades so I'll reset that option for the dual blade version and see if there are any improvements.