Uxcell #12 x 32mm 410 Stainless Steel Hex Washer Head Self Drilling Screws 50 Pack Self-drilling screw in addition to the tap-like flute in the leading threads there is also a drill-like fluted tip that looks much like the tip of a center drill. These screws combine a threading-like action and the fastener installation itself into only one driving motion (instead of separate drilling tapping and installing motions); they are thus very efficient in a variety of hard-substrate applications from assembly lines to roofing.
