What is the disadvantage of threaded fasteners?

Well, most of the threaded fasteners used in general applications have the following disadvantages:

1. Continued exposure to vibration tends to loosen the fastener.

2. If the fasteners are not creep resistant, they will fail at elevated temperatures.

3. The sharp edges formed in the threads of the members acts as stress concentration regions and is undesirable. This is to some extent overcome by introducing a small radius at the crests and troughs of the threads.