The bolt holes of the usual flanges have an upward allowance. Instead of a positive or negative margin, the problem is that the bolt hole must ensure that the bolt can be inserted accurately. If it is slightly larger, there is no problem, because there are flat photoelectric products that can Protect this bolt hole, and then put the bolt on the back, this is no problem, but if the bolt hole of the flange product is too small and the bolt cannot be inserted, this product is equivalent to waste, useless Now, if you choose a slightly thinner bolt, it will not be in line with the craftsmanship, and it will not pass through the craftsmanship, and it will not be allowed by the craftsmanship, so the processing of the bolt holes is slightly larger, no problem, but it will not work if it is too small. . But it's not too big. This moon has such a moon in our flange standard books, indicating that there is an introduction to such a process.
Classification of bolt holes:
1. Hexagonal head type: one is flat and the other is concave.
2. Surface color category: According to different needs, the surface is plated with white, military green, colorful yellow, and corrosion-resistant Dacromet.
3. Flange plate type: According to the different positions of flange bolts, the size of the plate is different, and there are flat bottom and toothed ones, and the toothed ones play a non-slip effect.
4. According to the force mode of the connection, there are ordinary ones and those with reaming holes. The flange bolts used for reaming holes should be matched with the size of the holes and are used when subjected to lateral force.
