Use of self - tapping combination screw

As a small series of macrocosm screws, I think there are three points to look at this problem, 1. What is the combination screw? 2. The function of combination screws? 3. Advantages of combination screws?

Assembly screw

I. what is combination screw

1. What is a combination screw

Combination screw usually refers to a screw with a spring pad with a flat pad by rubbing teeth, combined with fastening together combination. And two combination screw is to point to a screw only match a spring pad or only match a flat pad, or can only match a flower tooth two combination. The country label of combination screw is indicated by GB9074. The commonly used cross groove small disk head three combination screw country label is GB9074.8. This.8 is for small plates. That is, the size of the head of the pan screw. Written as PM. Professional combination screw manufacturers, the customary method of expression is triple PM. And the commonly used cross groove large pan head combination screw country label is GB9074.4. The profession calls the combination screw of big pan head. Or R heads, or B heads. In other words, the head of the combination screw is larger and thicker than the head of the combination screw of the small disk head. Still have commonly used a kind is outside hexagon Angle combination screw, this kind is cross outside hexagon Angle combination screw. Often called the socket outside the hexagon combination screw. Country label is GB9074.13.

2. Material of combination screws

Combination screws are made of stainless steel and iron. Iron is made of different iron screws and wires. General combination screw wire is used 1010,1018,10 B21 and so on. 10B21 is used for 8.8 class combination screws. For example, 8.8 hexagon socket socket combination screws are usually made with 10B21 wire. After it's done, it goes to heat treatment. After heat treatment, remove hydrogen and electroplate. This is to prevent the hexagon socket assembly screw spring pad fracture. Stainless steel combination screw, combination screw market, generally refers to the stainless steel SUS304 combination screw. 201 combination screws generally do very little. Few combination screw manufacturers to produce 201 combination screw. Because the hardness of stainless steel 201 screw wire is not well controlled, it is easy to produce cracks.

Assembly screw

Two, the role of combination screw

Steel structure with high strength hexagon head bolt combination screw, mainly used for railway and highway Bridges, boiler steel structure, industrial buildings, high-rise civil buildings, tower mast structure, hoisting machinery and its steel structure need to use friction type high strength bolt combination screw occasions. It is characterized by a bolt, also known as the end of the bolt an extra dodecagon. When installing, must use tailor-made electric wrench, its upper and lower have two socket heads, one set on the hexagon nut, another set on the hexagon screw ten Angle body. When tightening, apply clockwise torque to the nut, apply equal counterclockwise torque to the dodecagon body of the bolt, so that the end of the outer hexagon screw and dodecagon body are connected with the neck to bear the torsional shear, until the neck is cut, the installation is finished. This type of high strength external hexagon screw for the primary screw, after installation generally can not be removed.

The function of combination screw is also very simple, it is the connection fastens the product thing, because it is smooth pad rub good tooth to go up in screw, need not match smooth pad when using. And in the use, the combination of screws and a particularly large role, is the role of anti-loosening.

Assembly screw

Three, the advantages of combination screw.

The advantage of combination screw lies in the use, save the time of hand match smooth pad at the same time, also improve some electronic appliances and other manufacturers to use the screw especially much screw efficiency. There are some special screw manufacturers, in some products when playing screw is needed to cooperate with the use of elastic pad. One by one. This is time-consuming, laborious and expensive.

● reduce product number, optimize inventory and logistics, save cost.

● reduce failures caused by human error, improper assembly, or forgetting to install the tamper washer.

● easy to assemble products of very small size.

● preassembly of components to ensure faster assembly speed.

● maintenance and repair can be performed in hard-to-reach or restricted areas.

● faster and easier to remove, loose gasket is difficult to remove, especially from the counterbore.

Matters needing attention

Environmentally friendly combination screws and non-environmentally friendly screws are invisible to the naked eye and require mechanical testing. You can't figure it out with the naked eye.

The combination screw of iron can be sucked up with magnet, the combination screw of stainless steel is very difficult to suck up.

The salt spray of the combination screw requires a salt spray machine to measure the number of hours.