Fastener SuperStore, Inc. Self-Drilling Screw 353755

12 X 1 Self-Drilling Screws / Phillips / Flat Head / #3 Point / 410 Stainless Steel Type BSD: A tapping screw with spaced threads and a drill point which drills its own hole. Type CSD: A wafer head thread forming screw with machine screw thread pitch and a drill point which drills its own hole. Both types allow the screw to form mating threads and produce a complete fastening system in a single operation. Type BSD: The 18-8 stainless drill screw offers superior corrosion resistance while the 410 stainless screw will drill through harder material than the 18-8. The hardness of the material to be drilled should be a minimum of 10-20 Rockwell hardness points. Minimum torques are the same for stainless and steel self-drill screws. Drill time is 2.5 seconds for a 1mm thick plate.