Cross groove semi-sunk self-drilling screw

Self-tapping screw material can be divided into carbon steel and stainless steel two kinds, its medium carbon steel material is usually mainly used in 1022 medium carbon steel. Usually used on doors and windows, iron sheets. The head is a bearing surface formed at one end. For thread forming and thread cutting self-tapping screws (self-tapping screws), the flat head is buried down (Flat? Countersunk), flat round head (Oval Countersunk), disc head (Pan), hexagonal and hexagon hua silk head (Hex and Hex washer Head) is the most important, these five head types account for almost 90% of all self-attack screws, using self-attack screws (self-attack screws) should first consider this.