Hexagon flange bolt: hexagonal head and flange together with thread.
Ordinary bolt heads are very thick and difficult to deform. If vibration occurs, they need to be re-tightened. The thin part of the flange can be slightly deformed and can be locked more firmly. Also, if you go up to the hole, there is no way to use the tool for the ordinary bolt. The flange bolt has a smaller head, and the lower flange also plays a fastening role, but can be used to go to the hole with a special tool. , about the same principle as the hexagon socket bolt. Then there is the flat top pad for the flange, which is safer on softer, non-wearable materials and does not cause perforation.