Cross Recessed Countersunk Head Self-extruding Screw

The cross recessed countersunk head self-extruding screw is a relatively special fastener. The following is the relevant information about the cross recessed countersunk head self-extruding screw:

Structural Characteristics of the Cross Recessed Countersunk Head Self-extruding Screw

Head: It is designed as a countersunk head, which is flat and has an inclined surface around it. After installation, the head can be flush with or slightly lower than the surface of the connected part, which can reduce the impact on other components and improve the aesthetics. There is a cross recess on the head, which is used to cooperate with a cross screwdriver for tightening or loosening operations, which is convenient and quick.

Screw Shank: Similar to the hexagon head self-extruding screw, the end of the thread is designed with a section of thread having an arc-shaped triangular cross-section. When screwing into the pre-drilled hole, the three vertices of the triangular cross-section will apply intermittent and periodic pressure to the side wall of the pre-drilled hole, causing the base material on the inner wall of the pre-drilled hole to be extruded and pushed into the thread flanks and the root of the thread along the thread lead, thus forming an internal thread.

Advantages of the Cross Recessed Countersunk Head Self-extruding Screw

Low Screw-in Torque: Compared with ordinary self-tapping screws that form internal threads by cutting, the cross recessed countersunk head self-extruding screw forms internal threads by extrusion. The screw-in frictional resistance is small, and it is more labor-saving.

High Locking Performance: When the screw is screwed in, the triangular cross-section at the tail of the thread extrudes the metal to form an internal thread, making the thread fit clearance small, and it can even achieve the effect of the metal "locking" the screw. The connection is stable, and the anti-loosening performance is good.

Aesthetic and Practical: The countersunk head design makes the surface flat after installation, which not only ensures the connection strength but also has a good appearance. It is suitable for occasions with high requirements for surface flatness and aesthetics.

Application Scenarios of the Cross Recessed Countersunk Head Self-extruding Screw

Electronic Devices: It is widely used in the assembly of electronic products, such as the assembly of the casings of computers, mobile phones, tablets and other devices, and the fixing of internal circuit boards. The low screw-in torque can avoid damaging fragile electronic components, and the high locking performance can ensure that the screws will not loosen due to vibrations during the use of the devices.

Furniture Manufacturing: It is often used to connect wood materials and fix various parts of furniture, such as the assembly of tables, chairs, cabinets, etc. It is easy to install, and it can make the surface of the furniture flat and beautiful. At the same time, the good locking performance can ensure the structural stability of the furniture.

Automobile Manufacturing: It can be used for the connection of automobile bodies and internal components, seat installation and other parts. It can withstand the vibrations and various stresses during the driving process of the vehicle, and ensure the reliability and safety of the connection.

Other Fields: It is also applied in some industries with high requirements for appearance, such as machinery manufacturing, instrument manufacturing, and the connection of some decorative components in building decoration.

Selection Method of the Cross Recessed Countersunk Head Self-extruding Screw

Selection According to the Material: For materials such as non-alloy, low-alloy, aluminum and aluminum alloys, copper and copper alloys (with a copper content greater than 63%), and zinc and zinc alloys with a tensile strength σb ≤ 600 N/mm², cross recessed countersunk head self-extruding screws of ordinary materials can usually be selected. For materials with poor plastic deformation ability or prone to work hardening, such as stainless steel, gray cast iron, and magnesium alloy, they can also be used under certain usage conditions, but a cautious evaluation is required. If there is a risk of corrosion in the usage environment, screws made of stainless steel should be selected.

Selection According to the Specification: Determine the appropriate diameter and length specifications according to the thickness of the connected part and the requirements for the connection strength. Generally, when the connected part is thicker or a greater connection strength is required, screws with a larger diameter and a longer length should be selected; conversely, screws with smaller specifications should be selected. At the same time, it is necessary to ensure that the length of the screw is sufficient to completely pass through the connected part and form an effective connection, but it should not be too long to avoid excessive exposure, which will affect the appearance or cause potential safety hazards.

Installation Key Points of the Cross Recessed Countersunk Head Self-extruding Screw

Pre-drilled Hole Processing: Before installation, a suitable pre-drilled hole needs to be processed according to the screw specification and the material of the connected part. The diameter of the pre-drilled hole needs to be precisely controlled. The diameter of the pre-drilled hole varies slightly for base materials of different materials and thicknesses to ensure the fitting effect between the screw and the pre-drilled hole.

Ensure the Surface is Clean: Clean the surface of the connected part thoroughly to remove impurities such as oil stains, dust, and rust, ensuring good contact between the screw and the surface and improving the reliability of the connection.

Screw in Vertically: Use a screwdriver or other suitable tools to screw the screw vertically into the surface of the connected part, avoiding tilting or eccentricity, otherwise it may lead to thread damage or an insecure connection. If an electric tool is used, pay attention to controlling the rotation speed and torque to prevent damage to the screw or the connected part due to too high a rotation speed or too large a torque.

Control the Screw-in Depth: According to the thickness of the connected part and actual needs, control the screw-in depth of the screw well. Avoid screwing in too deeply, which may cause the screw to penetrate the connected part or damage the internal structure, and do not screw in too shallowly to avoid an insecure connection.