My corded Skil drill has a "Jacobs" taper fitting chuck.That's why I
can't see a screw when I look down the chuck. I know this because I was
using a 1" dia masonry bit in it and the vibration shook the chuck off
the drill. It wouldn't stay on after that until I let the drill cool
and heated the chuck to shrink it on. When the chuck finally failed I
heated it to get it off so I could replace it. Hope this helps!