What type of rivet head is designed to sit flush with the surface material once installed?

The flush head rivet is designed specifically to sit flush with the surface material once installed. This type of rivet head is essential in applications where aerodynamics are a concern, as having a smooth surface helps to minimize drag and turbulence. It is particularly useful in the aerospace industry where maintaining a sleek profile on the aircraft structure can significantly enhance performance and efficiency.

In contrast, standard and protruding head rivets typically have heads that extend above the surface, which can create unevenness that may not be suitable for applications requiring a streamlined profile. While flat head rivets also have a low profile, they do not sit as flush against the surface as flush head rivets, making them less desirable for applications where aerodynamic efficiency is critical. Thus, the flush head rivet is the optimal choice for achieving a smooth and aerodynamic surface finish.