What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
R-type plastic rivets, also known as expansion rivets, are composed of plastic sub-nails and female buckles. It is not necessary to use installation tools during installation, place the installation base in the smooth hole, and then press the head, the specially designed feet expand and stretch after being stressed, and are firmly locked on the installation surface. It is often used to connect plastic shells, lightweight boards, insulating materials, circuit boards, or any other thin, light-weight materials. It is beautiful, practical, and easy to use.
When used for the connection and fixation of doors, windows, cabinets, etc. involving hinges, the traditional screw fastening method is usually used, and the screws are directly driven into the screw holes of the connected parts, and the screw end caps are directly exposed, which not only affects the connected parts. Moreover, the end caps of the screws exposed for a long time are easy to rust, and there are burrs in the end processing of the general screws. When used for fastening connections, the end caps of the screws are easy to scratch people, which affects the appearance and is not safe.
A screw can be equipped with only one spring washer or only one flat washer, or it can also only be equipped with a two-piece combination of flower teeth. The national standard number of the combination screw is represented 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. That is, the size of the head of the pan head screw that is often said. Denoted by letters as PM. Professional combination screw manufacturers, the habitual expression method is three-in-one PM. The commonly used cross recessed large pan head combination screw national standard is GB9074.4. Professionally called large pan head combination screws. 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.
At present, in the production workshop, there is no special tool for removing rivets such as skew, wrong rivets, and multiple rivets. When removing these rivets, workers use homemade rivet removal tools, use a sledgehammer to remove the rivet head, and then use a sharp tool to remove the rivet rod. eject. During the removal operation, sometimes the rivet head will fly out, the speed is high, the danger is extremely high, and the labor intensity is high, which has caused many industrial accidents.
The above content is uploaded by Yueluo or the Internet. If there is any copyright issue, please contact [email protected].
