I have a few screws (flat head) that the flat head slot had worn out, and
since the screw is a finish screw it is recessed deep into the surface so
cutting a new slot with a dremel for example is not practical.

So after a few tries I decided to get a screw extractor. I bought one at
the right size at HD brand name KOBALT.

I used the drill bit and drilled a hole about 1/4" deep. Then I took the
other piece that is called the "plug tab" and put that into the hole and
turned it counterclockwise with a wrench. The plug tab turned but the screw
stays. I then use a hammer and lightly tapped the plug tab deeper into the
hole, turned again and same result.

I thought it's supposed to "grab" the inside surface and turn the screw but
it didn't.

So either I am not using it right, or I did not drill deep enough, or this
is a piece of crap screw extractor and I need to get a good one.

Any idea what I should do?

MC