METRIC DIN N/A ISO N/A BS N/A
WINGED SELF-DRILLERS ARE DESIGNED TOO -
THE DRILL POINT DRILLS THE TIMBER, AS THE WINGS COUNTER BORE THE HOLE LARGER THAN THE THREAD DIAMETER.
WITH THE HOLE BEING LARGER THE THREAD WILL NOT ENGAGE INTO THE TIMBER.
AFTER THE SELF-DRILLERS POINT DRILLS THROUGH THE METAL, THE WINGS BREAK OFF ON CONTACT WITH THE METAL.THE THREAD CUTTING FEATURE ON THE SHANK CUTS A MATING THREAD IN THE METAL AND THE THREAD CONTINUES TO ENGAGE. THE HEAD THEN CLAMPS DOWN FIRMLY TOGETHER.