What are the uses of combination screws
We sometimes use combination screws in life, but do you know anything about combination screws? Maybe few people now understand the combination screw. If you don't want to know, you can read this news. Combination screw A combination screw refers to a combination of a screw with a spring washer and a flat washer after rubbing the teeth, combined and fastened together. The two-combination screw refers to a screw with only one spring washer or only one flat washer, or it can also be equipped with only one flower tooth. The national standard number of the combination screw is indicated by GB9074. The commonly used cross recessed small pan head three combination screw national standard is GB9074.8. This .8 refers to the small pan head. Also known as the head size of the pan head screw. Indicated by letters as PM. Professional combination screw manufacturers, the habitual display method is three-in-one PM. The commonly used cross recessed large pan head combination screw national standard is GB9074.4. Professional combination screw called large pan head. Or R head, or B head. That is to say, the head of this combination screw is larger and thicker than the head of the small pan head combination screw. There is also a commonly used external hexagon combination screw, which is a cross external hexagon combination screw. It is often called a socket hexagon combination screw. The national label is GB9074.13.
High-strength hexagon head bolt combination screws for steel structures, mainly used in railway and highway bridges, boiler steel structures, industrial plants, high-rise civil buildings, tower and mast structures, hoisting machinery and their steel structures need to use friction-type high-strength bolt combinations for screws. It is characterized by an extra dodecagon at the end of the bolt, also known as the bolt. When installing, a special electric wrench must be used. There are two socket heads up and down, one is set on the hexagonal body of the nut, and the other is set on the decagon body of the outer hexagon screw. When tightening, apply a clockwise force to the nut, and apply an equal counterclockwise force to the dodecagon body of the bolt, so that the connection between the end of the outer hexagon screw and the dodecagon body is subjected to torsional shearing until the neck is sheared. So far, the installation is completed. This torsion shear type high-strength outer hexagon screw is a one-time use screw and generally cannot be removed after installation.
This is the introduction and use of the combination screw.
