What is the most common countersink angle used in aerospace?

The most common countersink angle used in aerospace is 100 degrees. This specific angle is advantageous because it effectively accommodates the typical head shapes of fasteners commonly used in aerospace applications, such as rivets and screws.

The 100-degree countersink angle provides a balanced fit that ensures proper seating of the fastener while also allowing for effective load distribution across the surface. This is crucial in aerospace where structural integrity and safety are paramount. The 100-degree angle minimizes the risk of stress concentrations that can occur at more acute angles, thus contributing to the durability and reliability of the assembly.

In contrast, angles such as 90 degrees offer less optimal fitting for standard aerospace fasteners and can result in uneven load distribution, potentially leading to performance issues. Angles greater than 100 degrees, such as 120 and 130 degrees, tend to be used in specific applications but are not the standard for general aerospace assembly. This makes the 100-degree countersink angle a preferred choice in the industry.