SELF DRILLING SCREWS
This screw with drilling the tail tip named as twist drill, screw during assembly to drill out the center by Confucius, and then with the aid of the nearby threaded portion on the carrier hole tapping squeeze cut out with the thread, so called the drilling and tapping screws.
Self drilling screw standerd
ANSI/ASME B18.64
GB/T 15856.1-2002
DIN7504N-1995
JIS B 1124-2003