‌Hexagonal socket head bolt vs ‌External hexagon head bolts: the differences between two bolts

Hexagonal bolts are a common fastener that connects and fixes two or more objects by tightening a nut. Its name comes from the design of six corners, which makes it easier to tighten with a wrench or spanner when rotating. Hexagonal bolts are divided into internal hexagonal bolts and external hexagonal bolts according to the appearance characteristics of the screw head. What is the difference between them? This article explores the difference between these two types of bolts.
 
The main differences between internal hexagonal screws and external hexagonal screws are appearance, tools used, installation space, strength and anti-slip performance, manufacturing cost, and applicable scenarios. ‌
 
Appearance and tools used

• ‌Hexagonal socket head bolt‌:  The screw head is rounded on the outside and has a concave hexagonal shape in the center. This design not only allows the head of the bolt to be more compact, but also allows the tool to be better embedded in the head of the bolt, providing good torque and reducing the possibility of slippage. Suitable for applications where space is limited. Hexagon socket head cap screws require a special hexagon wrench for tightening and removal. The wrenches for hexagon socket head bolts/screws are “L” shaped, with one side long and one side short, the short side screws the screws, and the hand holds the long side to save energy and better tighten the screws.
• ‌External hexagon head screws: The sides of the screw head are hexagonal in shape, with no recessed part. This design makes the head of the bolt wider, easy to use common wrenches or pliers for installation and removal, more convenient operation.

                
Installation space

• ‌Hexagonal socket head bolt‌: It occupies less space and can be installed in a deeper position. The head can sink into the part without being exposed, and the appearance is beautiful. It is suitable for occasions with limited space.
• ‌External hexagon head screw‌: It occupies a large space and is not suitable for environments with small spaces.

 
Strength and anti-slip performance

• ‌Hexagonal socket head bolt‌: It usually has higher strength and good anti-slip performance, because all six corners face inward and are not easy to loosen when subjected to outward pulling force.
• ‌External hexagon head screw‌: It has better strength and durability, but the anti-slip performance may be slightly inferior to that of internal hexagon screws.

 
Manufacturing costs and application scenarios

• Hexagon socket head screws: relatively high manufacturing costs, but in need of high-strength fastening and non-slip performance is more suitable for the occasion, commonly used in small equipment connections; aesthetics, precision and other requirements of high mechanical connections; the need for countersunk head occasions; narrow assembly occasions.
• ‌External hexagon head screw‌: lower manufacturing costs, widely used in a variety of environments and conditions, such as construction, bridges, vehicles, ships, etc., and has good interchangeability. In the connection of large equipment; thin-walled parts on or subject to shock, vibration or alternating load occasions; thread requirements for longer occasions; low cost, low power intensity, low precision requirements of the mechanical connection; do not consider the space of the occasion is equally applicable.

To sum up, hexagon head bolts and hexagon head bolts are different in many aspects, and customers can choose the right bolts according to specific application scenarios and actual needs.