1. Standard self-tapping screws can be identified by letter codes, each code representing a variety of different combinations of tooth type and end shape. There are generally two types of screw pattern for each self-tapping screw: machine screw and self-tapping thread. According to the shape of its end and the change of thread, self-tapping screw can be divided into ordinary self-tapping screw, self-cutting self-tapping screw, self-extruding self-tapping screw and self-drilling self-tapping screw four basic types.

Self-tapping screw is one of the threaded fasteners in the predrilling of metallic or non-metallic materials. Self-tapping screws are often used to connect thin metal plates (steel plates, saw plates, etc.). When connecting, first make the threaded bottom hole of the connected piece, then screw the tapping screw into the threaded bottom hole of the connected piece. Due to the high hardness (≥45HRC) of the threaded surface of the tapping screw, the internal thread can be tapped out in the threaded base hole of the connected piece, thus forming a connection.

Features:

Due to its self-forming or tapping its matching thread, it has high anti-loose ability in combination and can be loaded and unloaded. On the small screw its size, screw type, head type, tapping performance is almost unlimited for engineering purposes.

Classification:

The screw head has round head, flat head, half countersunk head and countersunk head. The material is generally carburized carbon steel, the surface hardness of the material after heat treatment is not less than 45HRC. Compared with ordinary screw threads, at the same large diameter, the pitch is larger and the path is smaller, has been standardized. Self-tapping screw material can be divided into carbon steel and stainless steel two kinds of carbon steel material usually with 1022 medium carbon steel. It's usually used for doors, Windows, and metal sheets. The head is a bearing surface formed by an enlarged portion of one end. For thread forming and thread cutting tapping screws, the Flat? Countersunk, OvalCountersunk, Pan, Hex and Hex washer Head are the most important. These five types account for almost 90% of all self-tapping screws. The other five other type for Flat concave bearing surface (Flat Undercut), Flat the whole edge (Flat Trim), Oval concave bearing surface (Oval Undercut), Flat the whole edge (Oval Trim) and the cylinder head (sloping hills Fillister) to compare the secondary head type, and incense top head. Thread rolling into self-drilling screw, self-tapping screw head type of choice, with the use of main consideration mushroom head (Truss), Round head and 100 degree flat head are not taken in the new design, cover its function can be replaced by other head, pan head can replace mushroom head and Round head, 82 degree flat head can replace 100 degree flat head, flat Round head, pan head, hexagon head and hexagon head.

Function:

Self-tapping locking screws are also used for connections between thin metal plates. The thread is an ordinary thread with curved triangular section, and the surface of the thread is also of high hardness. Therefore, when connecting, the screw can also tap out the internal thread in the bottom hole of the thread of the connected part, thus forming a connection. This screw is characterized by low torque and high locking performance, better performance than ordinary self-tapping screw, and can be used in place of machine screws.

Wall board self - tapping screws are used for connection between gypsum wall board and metal keel. The thread is double-headed and the thread surface is of high hardness (≥HRC53), which can be quickly screwed into the keel to form a connection without prefabricated holes.

The difference between the self-tapping screw and the common self-tapping screw is that the common self-tapping screw must go through two working procedures: drilling (drilling the threaded base hole) and tapping (including fastening connection). While the auger tapping screw is connected, the two processes of drilling and tapping are combined to complete once. It first USES the drill in front of the screw for drilling, and then USES the screw for tapping (including fastening connection) to save construction time and improve construction efficiency.

Pan head and hexagon head self-tapping screws are suitable for the occasions where the screw head is allowed to be exposed. Countersunk head and hexagon socket shaped self-tapping screw are suitable for occasions where the screw head is not allowed to be exposed. Semi countersunk head self tapping screws are suitable for situations where the screw head allows slight exposure. When assembling and disassembling the self-tapping screws, the slotted self-tapping screws need a type screw screwdriver, the cross-groove self-tapping screws need a cruciform screw screwdriver, the inner hexagon flower shaped self-tapping screws need an inner hexagon flower shaped wrench, and the hexagon head self-tapping screws need an open wrench, a box wrench or a adjustable wrench.