Hexagonal bolts are currently widely used in the fastener industry. Compared to straight and cross shaped heads, their assembly is less prone to slipping teeth and has higher torque. Compared to the twelve cornered and multi toothed heads, its structure is simple and its cost is low. Therefore, the comprehensive price of hexagonal bolts is relatively high.

Hexagonal bolts can be divided into internal hexagonal bolts and external hexagonal bolts. What are the differences between these two types of bolts? How to choose when applying?

1. From a cost perspective, the manufacturing cost of the head of an internal hexagonal bolt is higher than that of an external hexagonal bolt. According to analysis, the cost of an external hexagonal bolt of the same specification is only about half that of an internal hexagonal bolt;

2. If a large tightening torque (axial force) is required, use an outer hexagon bolt because the contact area at the bottom of the bolt head is larger. Note that the bearing surface of the outer hexagon washer series bolt is smaller than that of the inner hexagon;

3. When the bolt is long and requires full thread, choose an external hexagonal bolt because internal hexagonal bolts are rarely fully threaded when they are long;

4. If it needs to be used in situations with hinged holes, use external hexagon bolts, because hinged hole bolts are generally external hexagon bolts;

5. If you want to take up less space, you can sink the head (into the workpiece, flush and beautiful), and use hexagonal bolts.

Overall, it is recommended to prioritize the use of external hexagonal bolts and, if necessary, internal hexagonal bolts.