Update time：2014-04-03 Source: RFS
what is Self tapping screw:
A self-tapping screw can be used to join two pieces of plastic or metal with simple holes drilled into them. A "normal" screw requires one of the holes to be "tapped" - a spiral has to be cut into one of the holes to accept the screw. Tapping holes is something of a game of skill; the tapping tools use very hard, brittle steel and it's easy to break a tool in the hole.
Self tapping screw application:
Self tapping screw is to screw in something that needs to be screwed in the wall or anywere !