Service HotlineCountersunk head screws are mostly used after installation, and the surface of the parts cannot be raised, and the parts to be fastened have two thicknesses. Thickness, after the screw is tightened, there is still a part of the screw thread that does not enter the threaded hole. In this case, the countersunk head screw can definitely be tightened. There is usually a situation where the thickness of the fastened part is less than the height of the head of the countersunk head screw, which is commonly seen in sheet metal parts in mechanical equipment, such as the connection between the hinge of the chassis and the door and the box; the sheet metal of the equipment The connection of the cover to the equipment, etc. Due to the small thickness of the part, the tightened sheet metal part, the screw through hole completely becomes a conical hole, in this case, when the countersunk head screw is tightened, the screw head is not a tapered surface to press the sheet metal part , but the bottom of the screw head and the top of the threaded hole are squeezed. Although it feels that the screw is tightened, the sheet metal part is stuck instead of being pressed. In this case, although it feels that the screw is tightened, the sheet metal The gold pieces were indeed not tightened. This is a very common situation. Let’s talk about the reasons for the processing: the head cone of the countersunk screw has a 90° conical angle, and the apex angle of the newly bought drill is usually 118°-120°. Some workers who lack training do not know this angle is poor. It is often used to ream the hole with a 120° drill bit, which results in that when the countersunk head screw is tightened, it is not the conical surface of the head, but a line at the bottom of the screw head, which is one of the reasons why the so-called countersunk head screw cannot be tightened. , it's not the screw's fault.
A kind of screw provided by Yueluo, the rod body of the screw rod has a thread segment, and the two ends of the thread segment are respectively provided with annular and two convex rings. The nominal size of the thread segment, and the distance from the convex ring at the rear end of the screw in the screwing direction to the rod core is greater than the nominal size of the thread segment.
Anti-corrosion technology Stainless steel screws are made of metal, and there are four main methods for metal anti-corrosion, namely the properties of the material itself, the environment of use, the interface between materials and the environment, and the improvement of the metal structure design. If a complete anti-corrosion alloy is used to make stainless steel Screws, unless there is a special need, are not cost-effective in terms of economics, and it is also impractical to completely isolate the appearance of the screw from environmental elements that can cause corrosion. Improving the metal structure design can improve the influence of special circumstances under certain conditions, but the design of most stainless steel screws cannot be fully corrected, and its maintenance effect is not permanent, so this method cannot basically solve the problem, as long as it is on the surface. Top anti-corrosion, that is, surface anti-corrosion treatment is the most widely used method. The anti-corrosion treatment on the surface of stainless steel screws refers to the use of various methods to apply a protective layer on the metal surface. The purpose of avoiding or mitigating corrosion. The protection layer should be able to meet the following requirements: 1. Corrosion resistance, wear resistance, high hardness, 2. The structure is tight, intact, and the pores are small. 3. It has strong separation and good adhesion with the base metal. 4. It is evenly distributed and has a certain thickness. The maintenance layer is usually divided into two types: metal coating and non-metallic coating. Metal coating refers to the use of metal or alloy with strong corrosion resistance to form a maintenance layer on the surface of metal that is easy to corrode. This coating is also called plating. There are quite a few methods and varieties to produce metal coatings, the most common of which is electroplating, followed by molten metal immersion plating (hot dipping) and chemical surface treatment. Non-metallic coating refers to the use of organic polymer materials such as paint and inorganic materials such as ceramics to form a protective layer on the surface of metal equipment or parts. The protective layer can completely isolate the base metal from the environmental medium and prevent the base metal from corrosion due to contact. Corrosion is formed in the medium of stainless steel standard parts.
Beneficial effects The commonly used nuts and bolts in the prior art are in the shape of a hexagon, the fastening surface is a regular hexagonal plane, and there are six elastic surfaces, and the adjacent elastic surfaces intersect with a straight line, and the opposite elastic surfaces are parallel to each other, In this way, the tightening operation can be easily performed with conventional tools, which is convenient and practical. However, there are some special occasions where the nuts and bolts of this structure are not suitable. Guangdong Yueluo Hardware Industry Co., Ltd. changed the fastening surface into a pentagon shape, and the adjacent elastic surfaces are connected by an arc angle. sex.
In the repair process of the EDITION 700 gearbox, it is often necessary to replace the piston seal. When replacing the direct gear piston seal, the shaft spring retaining ring on it must be removed before the piston can be taken out for replacement. For the seal, since the piston return spring 3 presses the retaining ring 5 through the spring seat 4 (as shown in Figure 3), it cannot be taken out directly. It is necessary to press down the spring seat before taking out the retaining ring. Without special tools, it is not easy to remove the retaining ring. At present, it is a time-consuming, labor-intensive and unsafe job that requires multiple people to use a screwdriver and a prying board to forcefully squeeze and pry to remove the retaining ring.
We have many years of experience in the production and sales of screws, nuts, flat washers, etc. The main products are: solid positioning cylindrical pins, set combinations/screw nuts, closed sheep's eye machine screws, self-tapping socket threads and other products, we can provide you with The right fastener solution for you.
