Customized carbon steel internal plum blossom pan head and pointed tail plated with blue and white zinc, self tapping anti-theft and irregular slot screws

A flat key is a key that relies on two sides as the working surface and transmits torque by squeezing the key and keyway sides. It is often installed on the shaft. If used for a long time or in a poor working environment for a long time, it is inevitable that there will be dust, oil stains, etc. stuck between the flat key and the keyway. The flat key is difficult to remove due to the lack of a threaded hole for disassembly, and any carelessness during the disassembly process can cause damage to the flat key. Nowadays, the nails of well-known automatic nail feeders are formed by installing automatic nail feeders on the electric threads of existing modified handheld electric drills. The screw mouth cannot be moved or the angle cannot be changed. When installing screws in a narrow environment, a screw connection part with a screw head and a screw connection part connected to the screw head are obtained through shielding, and a transition part is set between the screws set in the screw connection part, The diameter of the transition part is smaller than the diameter of the screw, and the transition part is covered with a plastic washer. The inner ring of the plastic washer is polygonal, and the inner ring of the plastic washer uses plastic washers instead of traditional metal washers to avoid wear and tear on the connecting substrate. The inner hole of the plastic washer adopts a polygonal design, and the diameter of the inner circle of the plastic washer is smaller than the diameter of the screw, which is more common than the screw, When using an existing screwdriver to install screws, it is necessary to fix the screws with the left hand and turn the screwdriver with the right hand. However, the installation space is small, and there are many areas that cannot be reached by hands, making installation difficult. For example, when installing with a regular screwdriver on an aircraft, it is difficult to install the screws due to the inability to locate them, resulting in poor installation efficiency. In addition, when installing screws on the wings and body of the aircraft, the combination of the screwdriver and the screw is prone to sliding, and the blade of the screwdriver falls off, which can easily damage hands and the aluminum skin of the aircraft. The front soundproofing and insulation pad is used to absorb the heat and noise transmitted by the firewall, while also playing a role in insulation and vibration isolation, ensuring a relatively quiet and comfortable environment inside the car, and improving ride comfort. As shown in Figures 1 and 2, the fixation of the front wall sound insulation pad 101 with the vehicle body is generally achieved through the screw buckle 102. The screw 100 is clamped by the clamp 103 in the screw buckle 102, and the limit bar 104 in the screw buckle 102 clamps the screw 100. After the screw 100 is inserted into the screw buckle 102, the tail end of the screw 100 is exposed, which can easily scratch the operator when assembling other components. Moreover, the exposed screw 100 is also prone to rust, affecting the connection strength of the screw 100 and reducing the service life of the screw 101. Please refer to Figures 1-2. The screw cap protective cover includes a cover body 1 and a disassembly handle 2. The cover body 1 includes a hexagonal screw cap set part 11 and a clamped part 12 connected to one end of the hexagonal screw cap set part 11. The internal part of the clamped part 12 is a hollow structure connected to the hexagonal screw cap set part 11. The clamped part 12 is a circular structure, and the large diameter end of the circular structure is connected to the hexagonal screw cap set part 11, As a result, it is not easy to remove the cover body 1 with bare hands, achieving a good anti-theft effect. The size of the large diameter end of the circular structure is larger than the size of the hexagonal screw cap set part 11. The inner surface of each side wall of the hexagonal screw cap set part 11 is provided with a convex rib 13 in the middle, and one end of the convex rib 13 extends to the large diameter end of the circular structure