I really wanted to love this nozzle and in soft wood it could be perfect. I just drilled a 2x4 to run some piping and I used a nearly underpowered 7.5A drill bit, but every time the center screw pressed the surface against the stud, it jammed and I had to wriggle out. I tried the trick mentioned in the previous review of replacing the screw with a regular drill bit, but the round shank drill bits only turned in the middle. If I had a rotary drill with a hex shank as the center that a set screw could hold, only then would I be in business, but without that the drill would be useless. center and just used it like a forstner, but that left a "post" in the center of my hole that I had to punch out every 1/4 inch or so. with the flat side for the set screw and allows you to choose which one you need. The racquet is of course too worn to return it so it's just wasted money.