Flat-head rivet nuts have either a smooth or vertically grooved cylindrical portion. Vertically grooved rivet nuts are commonly used during production because their vertical grooves provide an anti-slip effect. The flat-head rivet nut's head protrudes through the sheet metal during riveting. Flat-head rivet nuts are also the most commonly used and durable type of rivet nut.
Countersunk head rivet nuts also have either a smooth or vertically grooved finish. They are riveted into thin sheets with chamfers. After installation, the head surface is parallel to the sheet metal surface. Available materials include galvanized iron, 304 stainless steel, and 316 stainless steel.
Small countersunk head rivet nuts are available in galvanized iron, 304 stainless steel, and 316 stainless steel. As the name suggests, small countersunk head rivet nuts have a smaller head diameter and thickness than countersunk head rivet nuts. If the sheet metal is thin and the chamfer is small or absent, a small countersunk head rivet nut is the only option.