Is it true that some manufactured rivet heads may not fall off after drilling them out?

The assertion is true because certain manufactured rivet heads can remain intact or partially attached after drilling them out, depending on factors such as the type of rivet and the method of installation. Rivets are designed with specific manufacturing processes, and some may exhibit stronger necks or varying material properties that affect how they behave during disassembly.

When a rivet is drilled, it typically creates a shear force that may not be sufficient to completely remove the head from the structure for all types of rivets. Additionally, if a rivet has been properly seated or if there are any oxide layers or other contamination at the interface, it may adhere more than expected, making it challenging to remove completely. Factors such as the drill bit used, the drilling speed, and the process applied can further influence whether the head comes off entirely.

In summary, it is accurate to say that there are instances where rivet heads may not completely detach during the removal process, supporting the correctness of the statement.