What type of rivet fits a 100 Degree countersink?

When dealing with countersunk rivets, it's essential to understand the relationship between the rivet head angle and the countersink angle. A 100-degree countersink is specifically designed to accommodate rivets with a matching 100-degree head angle.

The rivets that are suitable for a 100-degree countersink are typically those with a flat or low-profile design, which allows them to be flush with the surface of the material after installation. Option A correctly identifies a type of rivet that has a 100-degree head, making it the appropriate choice to ensure a proper fit and surface finish.

Choosing a rivet with a different head angle would result in improper seating within the countersink, which could lead to structural weaknesses or an uneven surface after installation. Thus, understanding the degrees of countersink and matching it with the correct rivet head is crucial for maintaining the integrity and quality of the construction in aerospace applications.