What are the two most commonly used rivet heads?

• A. MS20470 universal head and MS20436 100º countersunk head
• B. MS20470 pan head and MS20436 60º countersunk head
• C. MS20470 truss head and MS20436 flush head
• D. MS20470 universal head and MS20436 raised head

Answer: (A)

Rivet head design is about balancing strength with surface finish. The two most commonly used rivet heads in aircraft structure are the universal head and the 100-degree countersunk head. The universal head provides a broad bearing surface on the rivet shank, which makes it versatile and forgiving in a wide range of joints where the head will be visible or where there isn’t a need to seat the rivet flush. It distributes load well and is easy to install, so it ends up being the go-to choice for many structural connections. The 100-degree countersunk head is designed to sit flush with the surface, creating a smooth, aerodynamic exterior and reducing snag hazards. This flush finish is essential on skin surfaces where protruding heads would disrupt airflow or interfere with coverings. Since these two head styles cover the most common scenarios—visible, load-bearing joints and flush, streamlined surfaces—they appear far more often than other head types in regular aviation work. Other head styles exist for special cases, but they’re not as widely used for general aviation structures.