What are the characteristics of countersunk head screws in screws?

Screws include countersunk head triangular screw, wall board screw, self-tapping screw, hand screw, wood screw, machine screw, machine screw, fiberboard screw, self-tapping screw, triangular head screw, non-standard screw, etc. Countersunk head self-tapping screw includes DIN7972, DIN7982, etc. Then why is it called "countersunk head self-tapping screw"? What are the characteristics of the material?

What countersunk head tapping screw? What is the meaning of the "sinking head" in front?

Countersunk head means that the screw head is no higher than the fixed surface after the screw is tightened. Since the attack is to open a small hole without tapping teeth directly screw fixed!

Fibreboard nail and cross countersunk head self - tapping nail difference?

From the design and application of countersunk head self-tapping screw, we can know that countersunk head self-tapping screw and other self-tapping screw is not the best choice to apply on wood, for the following two reasons.

1: the thread of countersunk head self-tapping screw and other self-tapping screws is shallow, which cannot provide enough tension for wood such as particle board. Iron, on the other hand, has a higher hardness, so it provides enough tension.

2: screw into the connection will form a threaded hole, the shallower the thread, the smaller the deformation, such as iron in the case of enough tension is naturally the smaller the deformation is easier to screw in.

3. Self-tapping screws are mostly used for connection between 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.